Output frame correction for unstable video streams

Techniques for output frame correction for unstable video streams are described herein. A video item may be transmitted via an input video stream from a first entity to a second entity over one or more electronic communications networks. The incoming frames from the input video stream may then be used, by the second entity, to generate an output video stream for presentation to one or more viewers. The transmission of the input video stream may temporarily become unstable and may be interrupted such that one or more frames of the input video stream are delayed and/or lost. When a transmission interruption is detected, the output video stream may be adjusted by inserting one or more correction frames into the output video stream. The inserted correction frames may include one or more repetitions of one or more prior frames in the output video stream and/or one or more interpolated frames.

BACKGROUND

The use of electronic communications networks for transmission of video content has increased rapidly in recent years. In many examples, video content may be transmitted using streaming technology, which may allow portions of a video content item to be presented to a viewer at the same time that subsequent portions of the video content are being transmitted. In order to maintain a sufficient transmission speed and/or quality, streaming video transmissions may generally require a generally stable network connection between senders and receivers. However, conditions such as network congestion and saturation, encoding errors, Internet Service Provider (ISP) errors, and others may cause temporary unstable conditions at some points during the course of a streaming transmission. These unstable conditions may result in one or more frames within a transmission being lost or delayed. Some conventional video streaming systems may attempt to handle such problems using various approaches, such as temporarily freezing presentation of the output video stream on a particular frame, showing an icon (e.g., spinning circle) indicating that the transmission is interrupted, or inserting placeholder images or videos (e.g., advertisements, indications of technical difficulty, etc.). These conventional approaches may, however, be disturbing to users, for example because they may freeze and/or interrupt the presentation of the video content. When the frozen and/or interrupted video content resumes, there may be noticeable changes in positions and features of displayed objects, potentially resulting in a jumpy, inconsistent, and unnatural viewing experience.

DETAILED DESCRIPTION

Techniques for output frame correction for unstable video streams are described herein. In some examples, a video item, such as a video game, movie, news or sports broadcast, may be transmitted via an input video stream from a first entity to a second entity over one or more electronic communications networks. Upon receiving incoming image frames from the input video stream, they may be temporarily stored, by the second entity, in an input frame buffer. The incoming frames from the input video stream may then be used, by the second entity, to generate an output video stream for presentation to one or more viewers. The incoming frames may include timestamps that indicate an ordering of the frames. In some examples, under stable (e.g., non-interrupted) operating conditions, the output video stream may include transmitted image frames in the same order that they are transmitted by the first entity. In some cases, however, the transmission of the input video stream may become unstable and may be interrupted such that one or more frames of the input video stream are delayed and/or lost (i.e., not received by the second entity). In some examples, the second entity may examine the timestamps of the incoming frames in order to determine that such a transmission interruption has occurred. For example, a transmission interruption may be detected when there are gaps in the sequence of the incoming frames, when incoming frames are received out of sequence with respect to one another, and/or when no incoming frames are received within a particular time interval.

In some examples, when a transmission interruption is detected, the output video stream may be adjusted by inserting one or more correction frames into the output video stream. The inserted correction frames may include one or more repetitions of one or more prior frames in the output video stream and/or one or more interpolated frames. In particular, in some examples, one or more interpolated frames may be inserted between two original frames that are received from the first entity. An interpolated frame is a frame that is not included in the input video stream and that is inserted in the output video stream between two frames that are included in the input video stream (referred to hereinafter as original frames) based, at least in part, on interpolation of states of the original frames. An interpolated frame may be generated, for example, by identifying a state (e.g., location, rotation, orientation, size, color, etc.) of a particular object in each of the original frames between which the interpolated frame is inserted. The states of the object in the original frames may then be used to determine an interpolated (e.g., intermediate) state with which to depict the object in the interpolated frame. In some examples, in addition to the two original frames between which the interpolated frame is inserted, other frames may also be used to determine the interpolated state, such as by calculating an estimated rate of change of the state of an object.

When a transmission interruption is detected, a quantity of frames associated with the transmission interruption (e.g., a quantity of lost and/or delayed frames) may be determined. The quantity of correction frames that are inserted into the output stream may then be determined based, at least in part, on the quantity frames associated with the transmission interruption. For example, in some cases, the quantity of inserted correction frames may be equivalent to the quantity of frames associated with the transmission interruption. In some examples, the input buffer may be assigned to hold a designated quantity of incoming frames and may become temporarily depleted (e.g., may hold less than the designated quantity) after a transmission interruption has occurred. In some cases, equating the quantity of inserted correction frames to the quantity of frames associated with the transmission interruption may, upon completion of the insertion of the correction frames, allow the input frame buffer to re-filled to its designated quantity of input frames.

In some examples, insertion of the correction frames into the output stream in response to a detected transmission interruption may provide a number of advantages. For example, in some cases, insertion of the correction frames may allow a transmission interruption to be corrected without freezing or interrupting the output video stream. In particular, when an output stream is frozen or interrupted, viewers may be able to easily detect that a transmission interruption has occurred. By contrast, in some examples, the insertion of correction frames may cause viewers to be unable or hardly able to detect an occurrence of a transmission interruption. Additionally, freezing or interrupting of an output video stream may result in a jumpy and inconsistent appearance of the output video. By contrast, in some examples, insertion of correction frames may reduce these negative effects, allowing movements to appear less jarring and more natural.

FIG. 1is a diagram illustrating an example system100for output frame correction that may be used in accordance with the present disclosure. In the example ofFIG. 1, a second entity120receives an input video stream115from a first entity110. Second entity120may then, in turn, transmit an output video stream130to viewer140. The input video stream115and the output video stream130may be transmitted using one or more electronic communications networks, for example one or more local area networks (LANs) and/or one or more wide area networks (WANs), such as the Internet. The input video stream115and output video stream130may be transmitted using streaming video transmission techniques that allow portions of a video item to be viewed by viewer140while subsequent portions of the video item are being transmitted in input video stream115and/or output video stream130. For example, in some cases, input video stream115and output video stream130may be transmitted using real-time messaging protocol (RTMP) or another streaming video transmission protocol. As should be appreciated, in some examples, input and output video streams115and130may be encoded for transmission and decoded upon reception, for example by various encoding and decoding components (not shown inFIG. 1).

Input video stream115and output video stream130may be used for transmission of a video item, such as a video game, movie, news, sports, or other video media item. In some examples, the transmitted video item may be a live streaming video item that is captured, for example using a video camera, screen capture software, or another capture component, and then transmitted and viewed immediately or nearly immediately after being captured. Additionally, in some examples, first entity110may be a video game broadcaster and second entity120may be a video game streaming service. For example, first entity110may capture video from one or more video games, for example using screen capture software. First entity110may then transmit the captured video to second entity120. Second entity120may then, in turn, transmit the received video content to various streaming service subscribers, including viewer140.

Input video stream115and output video stream130may each include a series of transmitted image frames. As shown inFIG. 1, upon being received by second entity120, frames included in input video stream115are temporarily stored in input frame buffer121. The received frames are then extracted from input frame buffer121and queued in output frame buffer123for transmission via output video stream130. In some examples, input frame buffer121may be assigned to hold a particular designated quantity of input frames. The image frames received in input video stream115may include timestamps that indicate an ordering of the frames. In some examples, under stable (e.g., non-interrupted) operating conditions, frames may be inserted into output video stream130in the same order that they are received from input video stream115.

In some cases, however, the transmission of the input video stream115may be interrupted such that one or more frames of the input video stream115are delayed and/or lost (i.e., not received by the second entity120). The delay or loss of these frames may be caused, for example, by network congestion and saturation, encoding errors, Internet Service Provider (ISP) errors, and other conditions. In some examples, timestamp measurement components122may examine and measure the timestamps of the incoming frames received in input video stream115. For example, timestamp measurement components122may identify the timestamps of incoming frames and the respective times at which the incoming frames are received. Timestamp measurement components122may provide indications of these measurements to interruption detection components124, which may detect when a transmission interruption resulting in lost and/or delayed frames has occurred. In some cases, lost and/or delayed frames may be detected when there are gaps in the sequence of the incoming frames, when incoming frames are received out of sequence with respect to one another, and/or when no incoming frames are received within a particular time interval.

Referring now toFIG. 2, some examples of lost and delayed frames will now be described in detail. For purposes of simplicity, in the examples ofFIG. 2, the timestamps of the received frames are indicated by the frame number shown inFIG. 2. For example, frame101has a timestamp of101, frame102has a timestamp of102, and so on. At the top ofFIG. 2, an example293of lost frames is shown. In example293, frame101is received, followed by frame102, frame106, and then frame107. Thus, it can be determined that there is a three frame gap between frame102and frame106. Based on this gap, interruption detection components124may determine that frames103,104, and105are lost (as represented by the depiction of lost frames103,104and105on the top right ofFIG. 2). Accordingly, at operation291, interruption detection components124report to frame correction components125that there are three lost frames missing from input video stream115.

An example294of frame delay is shown at the bottom ofFIG. 2. In example294, frames are received under stable (e.g., non-interrupted) conditions at a rate of ten frames per second. As shown, frame101is received at time of 0.1 seconds, frame102is received at time of 0.2 seconds, frame103is received at time of 0.6 seconds, and frame104is received at time of 0.7 seconds. Thus, in this example, it may be determined that there is a 0.4 second gap between the receive times of frame102and frame103, which is 0.3 seconds longer than the expected gap of 0.1 seconds. There is, therefore, a 0.3 second delay between frame102and frame103. Under stable conditions, three frames would normally be transmitted during the 0.3 second delay between frame102and frame103. Based on these measurements, interruption detection components124may calculate that there is a three frame delay between frame102and frame103. Accordingly, at operation292, interruption detection components124report to frame correction components125that there is a three frame delay in the input video stream115.

Thus, as described above, upon detecting that a transmission interruption has occurred, interruption detection components124may report the interruption to frame correction components125, for example indicating a quantity of lost and/or delayed frames, which is also referred to herein as a quantity of frames associated with the transmission interruption. In some examples, frame correction components125may then, based at least in part on the quantity of frames associated with the transmission interruption, determine a quantity of correction frames to insert into output video stream130, for example via output frame buffer123. For example, in some cases, frame correction components125may insert, into output video stream130, a quantity of correction frames that is equivalent to the quantity of frames associated with the transmission interruption.

As set forth above, in some examples, the input frame buffer121may be assigned to hold a designated quantity of input frames received from input video stream115. This may, in some examples, help to ensure that the input frame buffer121retains a sufficient quantity of frames so as to allow the frame correction techniques described herein to be employed without freezing or interruption of the viewed video output. In some examples, when a transmission interruption occurs, the quantity of frames stored in the input frame buffer121may temporarily drop below the designated quantity of input frames that the input frame buffer121is assigned to hold. However, inserting, into the output video stream, a quantity of correction frames that is equivalent to the quantity of frames associated with the transmission interruption may be advantageous, for example, because it may help to ensure that, after insertion of the correction frames, the input frame buffer121returns to holding the designated quantity of input frames.

The inserted correction frames may, for example, include one or more repetitions of one or more previous frames inserted into output video stream130and/or one or more interpolated frames. In particular, in some examples, one or more interpolated frames may be inserted between two original frames that are received in the input video stream115. An interpolated frame is a frame that generally includes one or more interpolated object states, such as interpolated locations, rotations, orientations, colors, sizes, or other states relative to the original frames between which it is inserted. Some example interpolated frames and interpolation techniques will be described in greater detail below, for example with respect toFIGS. 4 and 5.

Referring now toFIG. 3, an example insertion of correction frames will now be described in detail. As shown at the top left ofFIG. 3, first entity110may transmit frames256-260in succession as part of input video stream115. The transmitted frames256-260may then be received by second entity120and stored in buffer390. It is noted that, in addition to frames256-260, buffer390may also include any number of additional frames (not shown). At the same times that frames256-260are being received by second entity120, frames196-200(which were received previously by second entity120) are being transmitted in output video stream130. Thus, in this example, under stable conditions, there is generally a sixty frame delay between a frames being received in input video stream115and frames being transmitted in output video stream130. For example, frame256is received in input video stream115when frame196is transmitted in output video stream130, frame257is received in input video stream115when frame197is transmitted in output video stream130, and so on. Referring now to the second row of illustrations inFIG. 3, it is seen that subsequent frames261-265are transmitted (or attempted to be transmitted) by the first entity110in succession as part of input video stream115. As shown, however, a transmission interruption has occurred between the transmission of frames261and265resulting in three frames (frames262-264) being lost (i.e., not received by the second entity120).FIG. 3indicates that frames262-264are lost by the designation (X) shown in frame numbers262(X),263(X), and264(X). As set forth above, these lost frames may be detected, for example, by determining that the timestamps of received frames have gone directly from261to265without the intervening timestamps262-264. At the same times that frames261and265are being received by second entity120, frames201-205(which were received previously by second entity120) are being transmitted in output video stream130.

In some examples, upon detecting that there are three lost frames associated with the transmission interruption between frames261and265, the second entity may, either immediately or at some future time, determine to insert three correction frames into output video stream130in order to correct for the three lost frames. Referring now to the third row of illustrations inFIG. 3, it is seen that subsequent frames266-270are transmitted by the first entity110in succession as part of input video stream115. At the same times that frames266-270are being received by second entity120, frames206-210(which were received previously by second entity120) are being transmitted in output video stream130. In this example, during the transmission of frames266-270, second entity120makes a determination to generate and insert three correction frames (represented by thick bold borders) between frames261and265. In particular, immediately following original frame261, second entity120inserts a first correction frame that is a repetition of frame261(indicated by the designation REP261inFIG. 3. Additionally, immediately following the repetition of frame261(REP261), second entity120inserts a second correction frame that is a first interpolation of original frames261and265(indicated by the designation INT(A) inFIG. 3). Furthermore, immediately following the first interpolation frame INT(A), second entity120inserts a third correction frame that is a second interpolation of original frames261and265(indicated by the designation INT(B) inFIG. 3).

Referring now to the bottom row of illustrations inFIG. 3, it is seen that subsequent frames321-325are transmitted by the first entity110in succession as part of input video stream115. Additionally, at the same times that frames321-325are being received by second entity120, frames261-265(including the three correction frames REP261, INT(A), and INT(B)) are being transmitted in output video stream130. Thus, by inserting these three correction frames into output video stream130, the techniques described herein allow the transmission interruption resulting in three lost frames262-264to be corrected without freezing or interruption of the output video stream130. In some examples, this may reduce or negate the jumpiness associated with freezing or interruption of the output video stream130, and a viewer of the output video stream130may be unable or only hardly able to notice that the transmission interruption in input video stream115had occurred.

In some examples, the input video stream115and the output video stream130may be transmitted using real time streaming techniques such that frames are displayed to one or more viewers140in real time (or near real time) after being transmitted in the input video stream115. In particular, in some cases, a frame may be viewed by viewer140instantaneously (or nearly instantaneously) after being transmitted in the input video stream115. For example, a frame may be captured by first entity110, instantaneously (or nearly instantaneously) transmitted to the second entity120via input video stream115, and then instantaneously (or nearly instantaneously) transmitted to the viewer140via output video stream130for viewing. Streaming protocols such as RTMP may, in some examples, be employed for use in real time streaming techniques. Additionally, in some examples, interpolating of frames and/or inserting of one or more correction frames into the output video stream130may be performed on-the-fly, for example during transmission of the input video stream115. For example, as shown inFIG. 3, correction frames REP261, INT(A), and INT(B) are inserted into buffer390for transmission in the output video stream130as frames266-270are being received in the input video stream115. Additionally, correction frames REP261, INT(A), and INT(B) are transmitted in the output video stream130as frames321-325are being received in the input video stream115.

As set forth above, in some examples, one or more interpolated frames may be inserted between two original frames that are received in the input video stream115. As also set forth above, an interpolated frame is a frame that includes one or more interpolated states, such as intermediate locations, rotations, orientations, colors, sizes, or other states relative to the original frames between which it is inserted. In particular, in some examples, an interpolated frame may be generated by identifying a state of a particular object in each of the original frames between which the interpolated frame is inserted. The state of the object in the original frames may then be used to determine an interpolated state with which to depict the object in the interpolated frame.

Some specific examples of interpolated frames will now be described in detail. In particular, referring now toFIG. 4, some examples of frame interpolation using object rotation will now be described. As shown,FIG. 4depicts examples of original frame261, a first interpolated frame INT(A), a second interpolated frame INT(B), and an original frame265are shown. In the example ofFIG. 4, original frame261includes a hand401with a finger pointing at zero degrees relative to a horizontal line across the frame (referred to hereinafter as a frame horizon). Additionally, original frame265includes the hand401with a finger pointing at ninety degrees relative to the frame horizon. Thus, it can be determined that the hand401has rotated ninety degrees from frame261to frame265. In the example ofFIG. 4, interpolated frames INT(A) and INT(B) are generated based on an assumption that the hand401has a constant rotational velocity between frames261and265and that the viewpoint in the frames has remained approximately the same. Additionally, in the example of 4, interpolated frame INT(A) is generated to represent an interpolation at a theoretical frame that is ⅓ between frames261and265(which would correspond approximately to theoretical frame262.33). Based on this, it can be calculated that, with a constant rotational velocity between frames261and265, hand401should be oriented in interpolated frame INT(A) at an angle thirty degrees relative to the frame horizon (i.e., ⅓ of the rotation from zero degrees to ninety degrees). Accordingly, as shown inFIG. 4, interpolated frame INT(A) depicts hand401at an angle of thirty degrees relative to frame horizon. Furthermore, in the example ofFIG. 4, interpolated frame INT(B) is generated to represent an interpolation at a theoretical frame that is ⅔ between frames261and265(which would correspond approximately to theoretical frame263.67). Based on this, it can be calculated that, with a constant rotational velocity between frames261and265, hand401should be oriented in interpolated frame INT(B) at an angle sixty degrees relative to the frame horizon (i.e., ⅔ of the rotation from zero degrees to ninety degrees). Accordingly, as shown inFIG. 4, interpolated frame INT(B) depicts hand401at an angle of sixty degrees relative to the frame horizon.

It is noted thatFIG. 4merely depicts one example technique for interpolation of a rotating object and that other interpolation techniques may be employed. For example, in some cases, an alternative technique may be employed in which both interpolated frames INT(A) and INT(B) show two images of hand401at both ninety degrees and zero degrees. Additionally, in some examples, the interpolated frames INT(A) and INT(B) may create an appearance of a rotation of hand401by showing the two images of the hand401at different levels of visibility (e.g., brightness, intensity, thickness, opaqueness, translucency, transparency, etc.). In some cases, objects may be made to appear less visible by being made less bright, less intense, less thick, less opaque, more translucent, more transparent, or using any combination of these or other techniques. Also, in some cases, objects may be made to appear more visible by being made more bright, more intense, more thick, more opaque, less translucent, less transparent, or using any combination of these or other techniques. For example, for cases in which INT(A) is associated with an angle of thirty degrees, INT(A) may include a first image of hand401at zero degrees depicted with a 66.7% visibility (relative to the visibility of hand401in frames261and/or265) and a second image of hand401at zero degrees depicted with a 33.3% visibility (relative to the visibility of hand401in frames261and/or265). Showing two images of the hand401in this manner may, in some examples, create the appearance that the hand401has rotated thirty degrees. Additionally, for cases in which INT(B) is associated with an angle of sixty degrees, INT(B) may include a first image of hand401at zero degrees depicted with a 33.3% visibility (relative to the visibility of hand401in frames261and/or265) and a second image of hand401at zero degrees depicted with a 66.7% visibility (relative to the visibility of hand401in frames261and/or265). Showing two images of the hand401in this manner may, in some examples, create the appearance that the hand401has rotated sixty degrees.

Referring now toFIG. 5, some examples of frame interpolation using object movement will now be described. In the example ofFIG. 5, original frame261includes a truck501at the left edge of the frame that is headed horizontally across the frame towards the right edge. Additionally, original frame265includes the truck501at the right edge of the frame. In the example ofFIG. 5, interpolated frames INT(A) and INT(B) are generated based on an assumption that the truck501has a constant velocity between frames261and265and that the viewpoint in the frames has remained approximately the same. Additionally, in the example ofFIG. 5, interpolated frame INT(A) is generated to represent an interpolation at a theoretical frame that is ⅓ between frames261and265(which would correspond approximately to theoretical frame262.33). Based on this, it can be calculated that, with a constant velocity between frames261and265, truck501should be located in interpolated frame INT(A) at a location that is ⅓ of the distance from the left edge of the frame to the right edge of the frame. Accordingly, as shown inFIG. 5, interpolated frame INT(A) depicts truck501at a location that is ⅓ of the distance from the left edge of the frame to the right edge of the frame. Furthermore, in the example of 5, interpolated frame INT(B) is generated to represented an interpolation at a theoretical frame that is ⅔ between frames261and265(which would correspond approximately to theoretical frame263.67). Based on this, it can be calculated that, with a constant velocity between frames261and265, truck501should be located in interpolated frame INT(B) at a location that is ⅔ of the distance from the left edge of the frame to the right edge of the frame. Accordingly, as shown inFIG. 5, interpolated frame INT(B) depicts truck501at a location that is ⅔ of the distance from the left edge of the frame to the right edge of the frame.

It is noted that, whileFIGS. 4 and 5depict example interpolations based on rotation and movement, other interpolations may also be performed based on other states, such as size, color, and many others. For example, in some cases, if an object changed color from red in frame261to yellow in frame265, the object could, in some examples, be depicted with a red-orange color in interpolated frame INT(A) and then with an orange-yellow in interpolated frame INT(B).

It is further noted that, while the above described examples are based on an assumption of a constant rate of change of state between frames261and265, the interpolation techniques described herein are not limited to constant rates of change and may also include examples in which a rate of change between states increases or decreases. For example, in the case ofFIG. 4, it may be possible that hand401is gradually slowing down its rate of rotation as it rotates from zero degrees to ninety degrees. In this case, the hand401may, in some examples, be depicted in interpolated frame INT(A) at an angle that is greater than thirty degrees, such as forty degrees. The hand401may also, in some examples, be depicted in interpolated frame INT(B) at an angle that is greater than sixty degrees, such as sixty-five degrees. In some examples, a rate of change of state may be determined by examining states of objects in additional frames besides the two frames between which an interpolated frame is inserted (e.g., frames259,266,258,267, and so forth). For example, if hand401rotates a greater distance between frames260and261than between frames265and266, then this may sometimes be determined to indicate that the rate of rotation of hand401is decreasing. By contrast, if hand401rotates a greater distance between frames265and266than between frames260and261, then this may sometimes be determined to indicate that the rate of rotation of hand401is increasing.

Thus, interpolation techniques such as those described above may sometimes be used to correct for lost or delayed frames, such as shown in the example ofFIG. 3. In the example ofFIG. 3, three correction frames (i.e., frames REP261, INT(A), and INT(B)) are inserted into the output video stream130at locations at which the lost frames262-264were detected (i.e., between received frames261-265). It is noted, however, that there is no requirement that correction frames must be inserted into the output video stream130at locations at which lost frames are detected and may, in some cases, be inserted at other locations. In particular, referring now toFIG. 6, an example will be described in which correction frames are inserted into output video stream in advance of locations at which lost frames are detected. As shown inFIG. 6, the second row of illustrations indicates that, just as in the prior example ofFIG. 3, a transmission interruption has occurred between the transmission of frames261and265resulting in three frames (frames262-264) being lost (i.e., not received by the second entity120).FIG. 6indicates that frames262-264are lost by the designation (X) shown in frame numbers262(X),263(X), and264(X).

Referring now to the third row of illustrations inFIG. 6, it is seen that second entity120makes a determination to generate and insert three correction frames (represented by thick bold borders) between frames206and207. In particular, immediately following original frame206, second entity120inserts a first correction frame that is a repetition of frame206(indicated by the designation REP206inFIG. 6). Additionally, immediately following the repetition of frame206(REP206), second entity120inserts a second correction frame that is a first interpolation of original frames206and207(indicated by the designation INT(A) inFIG. 6). Furthermore, immediately following the first interpolation frame INT(A), second entity120inserts a third correction frame that is a second interpolation of original frames206and207(indicated by the designation INT(B) inFIG. 6). Thus, as shown in the example ofFIG. 6, correction frames may, in some examples, be inserted into an output video stream at a location (i.e., between frames206and207) in advance of a location at which lost or delayed frames are detected (i.e., between frames261and265).

FIG. 7is a flowchart illustrating an example output frame correction process that may be used in accordance with the present disclosure. The process ofFIG. 7is initiated at operation710, at which a first portion of an input video stream of a transmitted video item is received. As set forth above, the transmitted video item may, for example, be a video game, news, or sports broadcast. In some examples, the input video stream may be received over one or more electronic communications networks, for example one or more local area networks (LANs) and/or one or more wide area networks (WANs), such as the Internet. The input video stream may be transmitted using streaming video transmission techniques that allow portions of the video item to be viewed while subsequent portions of the video item are being transmitted. In some examples, the transmitted video item may be a live streaming video item that is captured, for example using a video camera, screen capture software, or another capture component, and then transmitted and viewed immediately or nearly immediately after being captured. As also set forth above, the first portion of the input video stream may include one or more image frames. Upon being received, the one or more image frames may be temporarily stored in an input frame buffer.

At operation712, the one or more image frames included in the first portion of the input video stream are inserted into an output video stream of the video item. The output video stream may be provided for presentation to one or more viewers. As set forth above, in some examples, the output video stream may be transmitted for presentation to one or more viewers over one or more electronic communications networks, for example one or more local area networks (LANs) and/or one or more wide area networks (WANs), such as the Internet. The output video stream may be transmitted using streaming video transmission techniques that allow portions of the video item to be viewed while subsequent portions of the video item are being transmitted.

At operation714, a transmission interruption resulting in one or more lost or delayed image frames in the input video stream is detected. As set forth above, in some examples, image frames received in the input video stream may include timestamps that indicate an ordering of the frames. In some examples, the timestamps of the frames received in the input video stream may be examined and compared to a time at which the frames are received. In some examples, a transmission interruption may be detected when there are gaps in the sequence of the incoming frames, when incoming frames are received out of sequence with respect to one another, and/or when no incoming frames are received within a particular time interval. In particular, in the example ofFIG. 3described above, the first portion of the input video stream may include frames1through261. A transmission interruption may then be detected at frame261, which results in frames262-264being lost.

At operation716, one or more correction frames are inserted into the output video stream. As set forth above, correction frames are frames that are either a repetition of a previous image frame inserted into the output video stream or an interpolation of one or more image frames received in the input video stream. In particular, in the example ofFIG. 3described above, three correction frames are inserted into the output video streams. The three correction frames include a repetition of frame261(referred to as REP261) and two interpolations between frames261and265(referred to as INT(A) and INT(B)). Insertion of the correction frames may allow playing of the output video stream without freezing or interrupting the output video stream.

As set forth above, an interpolated frame may be generated based, at least in part, on a first and a second frame in the output video stream between which the interpolated frame is inserted. In some examples, generating of the interpolated frame may include determining a first state of an object in the first frame, determining a second state of the object in the second frame, determining, based at least in part on the first state and the second state, and interpolated state of the object in the interpolated frame, and generating the interpolated frame including the object with the interpolated state. The interpolated state may, in some examples, include a location, a rotation, an orientation, a color, a size, and/or another type of state. In some examples, in addition to the two original frames between which the interpolated frame is inserted, other frames may also be used to determine the interpolated state, such as by calculating an estimated rate of change of the state of an object.

In some examples, when a transmission interruption is detected at operation714, a quantity of frames associated with the transmission interruption (e.g., a quantity of lost and/or delayed frames) may be determined. The quantity of correction frames that are inserted into the output stream at operation716may then be determined based, at least in part, on the quantity frames associated with the transmission interruption. For example, in some cases, the quantity of inserted correction frames may be equivalent to the quantity of frames associated with the transmission interruption. In some examples, equating the quantity of inserted correction frames to the quantity of frames associated with the transmission interruption may, upon completion of the insertion of the correction frames, allow the input frame buffer to re-filled to its designated quantity of input frames.

At operation718, subsequent to the detected transmission interruption, a second portion of the input video stream is received. The second portion of the input video stream may include one or more image frames. In particular, in the example ofFIG. 3described above, the transmission interruption resulted in frames262-264being lost, and the second portion of the input video stream may include frames265and following. At operation720, the one or more image frames included in the second portion of the input video stream are inserted into the output video stream. In some examples, video data from the input video stream may be saved by the second entity prior to being transmitted to one or more viewers, such as in a video on demand (VOD) library or other collection of stored videos. Thus, in some examples, the output video stream as described above may instead be a video output, which may encompass either or both of an output video stream that is provided to the viewer by transmission over a communications network from the second entity to the viewer or a video output that is stored, for example by the second entity in a VOD library for future viewing.

It is also noted that, in some examples, the techniques described herein may be used in combination with other techniques, such as those in which one or more placeholder images (e.g., advertisements, indications of technical difficulty, etc.) are inserted into the output video stream. For example, in some cases, for extended transmission interruptions that include large quantities of lost or delayed frames, the second entity may begin to insert correction frames using the techniques described herein, for example until reaching a threshold quantity and/or duration of inserted correction frames. After reaching this threshold, the second entity could then switch to inserting one or more placeholder images.

An example system for transmitting and providing data will now be described in detail. In particular,FIG. 8illustrates an example computing environment in which the embodiments described herein may be implemented.FIG. 8is a diagram schematically illustrating an example of a data center85that can provide computing resources to users70aand70b(which may be referred herein singularly as user70or in the plural as users70) via user computers72aand72b(which may be referred herein singularly as computer72or in the plural as computers72) via a communications network73. Data center85may be configured to provide computing resources for executing applications on a permanent or an as-needed basis. The computing resources provided by data center85may include various types of resources, such as gateway resources, load balancing resources, routing resources, networking resources, computing resources, volatile and non-volatile memory resources, content delivery resources, data processing resources, data storage resources, data communication resources and the like. Each type of computing resource may be available in a number of specific configurations. For example, data processing resources may be available as virtual machine instances that may be configured to provide various web services. In addition, combinations of resources may be made available via a network and may be configured as one or more web services. The instances may be configured to execute applications, including web services, such as application services, media services, database services, processing services, gateway services, storage services, routing services, security services, encryption services, load balancing services, application services and the like. These services may be configurable with set or custom applications and may be configurable in size, execution, cost, latency, type, duration, accessibility and in any other dimension. These web services may be configured as available infrastructure for one or more clients and can include one or more applications configured as a platform or as software for one or more clients. These web services may be made available via one or more communications protocols. These communications protocols may include, for example, hypertext transfer protocol (HTTP) or non-HTTP protocols. These communications protocols may also include, for example, more reliable transport layer protocols, such as transmission control protocol (TCP), and less reliable transport layer protocols, such as user datagram protocol (UDP). Data storage resources may include file storage devices, block storage devices and the like.

Data center85may include servers76aand76b(which may be referred herein singularly as server76or in the plural as servers76) that provide computing resources. These resources may be available as bare metal resources or as virtual machine instances78a-d(which may be referred herein singularly as virtual machine instance78or in the plural as virtual machine instances78). Virtual machine instances78cand78dare frame correction virtual machine (“FCVM”) instances. The FCVM virtual machine instances78cand78dmay be configured to perform all, or any portion, of the frame correction techniques and/or any other of the disclosed techniques in accordance with the present disclosure and described in detail above. As should be appreciated, while the particular example illustrated inFIG. 8includes one FCVM virtual machine in each server, this is merely an example. A server may include more than one FCVM virtual machine or may not include any FCVM virtual machines.

Referring toFIG. 8, communications network73may, for example, be a publicly accessible network of linked networks and possibly operated by various distinct parties, such as the Internet. In other embodiments, communications network73may be a private network, such as a corporate or university network that is wholly or partially inaccessible to non-privileged users. In still other embodiments, communications network73may include one or more private networks with access to and/or from the Internet.

Communication network73may provide access to computers72. User computers72may be computers utilized by users70or other customers of data center85. For instance, user computer72aor72bmay be a server, a desktop or laptop personal computer, a tablet computer, a wireless telephone, a personal digital assistant (PDA), an e-book reader, a game console, a set-top box or any other computing device capable of accessing data center85. User computer72aor72bmay connect directly to the Internet (e.g., via a cable modem or a Digital Subscriber Line (DSL)). Although only two user computers72aand72bare depicted, it should be appreciated that there may be multiple user computers.

User computers72may also be utilized to configure aspects of the computing resources provided by data center85. In this regard, data center85might provide a gateway or web interface through which aspects of its operation may be configured through the use of a web browser application program executing on user computer72. Alternately, a stand-alone application program executing on user computer72might access an application programming interface (API) exposed by data center85for performing the configuration operations. Other mechanisms for configuring the operation of various web services available at data center85might also be utilized.

Servers76shown inFIG. 8may be servers configured appropriately for providing the computing resources described above and may provide computing resources for executing one or more web services and/or applications. In one embodiment, the computing resources may be virtual machine instances78. In the example of virtual machine instances, each of the servers76may be configured to execute an instance manager80aor80b(which may be referred herein singularly as instance manager80or in the plural as instance managers80) capable of executing the virtual machine instances78. The instance managers80may be a virtual machine monitor (VMM) or another type of program configured to enable the execution of virtual machine instances78on server76, for example. As discussed above, each of the virtual machine instances78may be configured to execute all or a portion of an application.

In the example data center85shown inFIG. 8, a router71may be utilized to interconnect the servers76aand76b. Router71may also be connected to gateway74, which is connected to communications network73. Router71may be connected to one or more load balancers, and alone or in combination may manage communications within networks in data center85, for example, by forwarding packets or other data communications as appropriate based on characteristics of such communications (e.g., header information including source and/or destination addresses, protocol identifiers, size, processing requirements, etc.) and/or the characteristics of the private network (e.g., routes based on network topology, etc.). It will be appreciated that, for the sake of simplicity, various aspects of the computing systems and other devices of this example are illustrated without showing certain conventional details. Additional computing systems and other devices may be interconnected in other embodiments and may be interconnected in different ways.

In the example data center85shown inFIG. 8, a server manager75is also employed to at least in part direct various communications to, from and/or between servers76aand76b. WhileFIG. 8depicts router71positioned between gateway74and server manager75, this is merely an exemplary configuration. In some cases, for example, server manager75may be positioned between gateway74and router71. Server manager75may, in some cases, examine portions of incoming communications from user computers72to determine one or more appropriate servers76to receive and/or process the incoming communications. Server manager75may determine appropriate servers to receive and/or process the incoming communications based on factors such as an identity, location or other attributes associated with user computers72, a nature of a task with which the communications are associated, a priority of a task with which the communications are associated, a duration of a task with which the communications are associated, a size and/or estimated resource usage of a task with which the communications are associated and many other factors. Server manager75may, for example, collect or otherwise have access to state information and other information associated with various tasks in order to, for example, assist in managing communications and other operations associated with such tasks.

It should also be appreciated that data center85described inFIG. 8is merely illustrative and that other implementations might be utilized. It should also be appreciated that a server, gateway or other computing device may comprise any combination of hardware or software that can interact and perform the described types of functionality, including without limitation: desktop or other computers, database servers, network storage devices and other network devices, PDAs, tablets, cellphones, wireless phones, pagers, electronic organizers, Internet appliances, television-based systems (e.g., using set top boxes and/or personal/digital video recorders) and various other consumer products that include appropriate communication capabilities.

In at least some embodiments, a server that implements a portion or all of one or more of the technologies described herein may include a computer system that includes or is configured to access one or more computer-accessible media.FIG. 9depicts a computer system that includes or is configured to access one or more computer-accessible media. In the illustrated embodiment, computing device15includes one or more processors10a,10band/or10n(which may be referred herein singularly as “a processor10” or in the plural as “the processors10”) coupled to a system memory20via an input/output (I/O) interface30. Computing device15further includes a network interface40coupled to I/O interface30.

In various embodiments, computing device15may be a uniprocessor system including one processor10or a multiprocessor system including several processors10(e.g., two, four, eight or another suitable number). Processors10may be any suitable processors capable of executing instructions. For example, in various embodiments, processors10may be embedded processors implementing any of a variety of instruction set architectures (ISAs), such as the x86, PowerPC, SPARC or MIPS ISAs or any other suitable ISA. In multiprocessor systems, each of processors10may commonly, but not necessarily, implement the same ISA.

System memory20may be configured to store instructions and data accessible by processor(s)10. In various embodiments, system memory20may be implemented using any suitable memory technology, such as static random access memory (SRAM), synchronous dynamic RAM (SDRAM), nonvolatile/Flash®-type memory or any other type of memory. In the illustrated embodiment, program instructions and data implementing one or more desired functions, such as those methods, techniques and data described above, are shown stored within system memory20as code25and data26.

In one embodiment, I/O interface30may be configured to coordinate I/O traffic between processor10, system memory20and any peripherals in the device, including network interface40or other peripheral interfaces. In some embodiments, I/O interface30may perform any necessary protocol, timing or other data transformations to convert data signals from one component (e.g., system memory20) into a format suitable for use by another component (e.g., processor10). In some embodiments, I/O interface30may include support for devices attached through various types of peripheral buses, such as a variant of the Peripheral Component Interconnect (PCI) bus standard or the Universal Serial Bus (USB) standard, for example. In some embodiments, the function of I/O interface30may be split into two or more separate components, such as a north bridge and a south bridge, for example. Also, in some embodiments some or all of the functionality of I/O interface30, such as an interface to system memory20, may be incorporated directly into processor10.

Network interface40may be configured to allow data to be exchanged between computing device15and other device or devices60attached to a network or networks50, such as other computer systems or devices, for example. In various embodiments, network interface40may support communication via any suitable wired or wireless general data networks, such as types of Ethernet networks, for example. Additionally, network interface40may support communication via telecommunications/telephony networks, such as analog voice networks or digital fiber communications networks, via storage area networks such as Fibre Channel SANs (storage area networks) or via any other suitable type of network and/or protocol.

In some embodiments, system memory20may be one embodiment of a computer-accessible medium configured to store program instructions and data as described above for implementing embodiments of the corresponding methods and apparatus. However, in other embodiments, program instructions and/or data may be received, sent or stored upon different types of computer-accessible media. Generally speaking, a computer-accessible medium may include non-transitory storage media or memory media, such as magnetic or optical media—e.g., disk or DVD/CD coupled to computing device15via I/O interface30. A non-transitory computer-accessible storage medium may also include any volatile or non-volatile media, such as RAM (e.g., SDRAM, DDR SDRAM, RDRAM, SRAM, etc.), ROM (read only memory) etc., that may be included in some embodiments of computing device15as system memory20or another type of memory. Further, a computer-accessible medium may include transmission media or signals such as electrical, electromagnetic or digital signals conveyed via a communication medium, such as a network and/or a wireless link, such as those that may be implemented via network interface40.

A compute node, which may be referred to also as a computing node, may be implemented on a wide variety of computing environments, such as commodity-hardware computers, virtual machines, web services, computing clusters and computing appliances. Any of these computing devices or environments may, for convenience, be described as compute nodes.

As set forth above, content may be provided by a content provider to one or more clients. The term content, as used herein, refers to any presentable information, and the term content item, as used herein, refers to any collection of any such presentable information. A content provider may, for example, provide one or more content providing services for providing content to clients. The content providing services may reside on one or more servers. The content providing services may be scalable to meet the demands of one or more customers and may increase or decrease in capability based on the number and type of incoming client requests. Portions of content providing services may also be migrated to be placed in positions of reduced latency with requesting clients. For example, the content provider may determine an “edge” of a system or network associated with content providing services that is physically and/or logically closest to a particular client. The content provider may then, for example, “spin-up,” migrate resources or otherwise employ components associated with the determined edge for interacting with the particular client. Such an edge determination process may, in some cases, provide an efficient technique for identifying and employing components that are well suited to interact with a particular client, and may, in some embodiments, reduce the latency for communications between a content provider and one or more clients.

In addition, certain methods or process blocks may be omitted in some implementations. The methods and processes described herein are also not limited to any particular sequence, and the blocks or states relating thereto can be performed in other sequences that are appropriate. For example, described blocks or states may be performed in an order other than that specifically disclosed, or multiple blocks or states may be combined in a single block or state. The example blocks or states may be performed in serial, in parallel or in some other manner. Blocks or states may be added to or removed from the disclosed example embodiments.