h264: check that an IDR NAL only contains I slices

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC:libav-stable@libav.org
avcodec/dnxhdenc: return meaningful return codes

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
lavf: add probe device API

Adds new API dedicated for output devices.

This API allows to
- Test device with provided configuration
  Audio devices params:
    - device name
    - codec
    - sample format
    - channel count
    - channels layout
    - sample rate
  Video devices params:
    - device name
    - codec
    - pixel format
    - width (minimal width as input and real width as output)
    - height (minimal height as input and real height as output)

- Get all supported configurations matching provided filter.
  Filter may contain any subset of Audio/Video device params.

Behaviour of probe function can also be modified by flags.

Signed-off-by: Lukasz Marek <lukasz.m.luki@gmail.com>
lavd/fbdev_enc: implement probe device

Signed-off-by: Lukasz Marek <lukasz.m.luki@gmail.com>
lavd/pulse_audio_enc: implement probe device

PulseAudio output device can be queried for valid configurations.
Wanted configuration may be passed to limit output for expected configuration.
Configuration are validated by initializing the device.

Signed-off-by: Lukasz Marek <lukasz.m.luki@gmail.com>
lavd/xv implement probe device
lavf: add control message API

New API allows communication between application and devices.

Signed-off-by: Lukasz Marek <lukasz.m.luki@gmail.com>

Conflicts:
	libavformat/avformat.h
lavd: add opengl device

It can render to OpenGL context provided by application or into SDL window

Signed-off-by: Lukasz Marek <lukasz.m.luki@gmail.com>
opengl probe device dummy

Conflicts:
	libavdevice/opengl_enc.c
libavengine
pause
callbacks
set pulse buffer to 100ms
add API to pause clocks
Pause clocks on pause
callback on pause status
partial seek api
avengine_is_media_opened function
read thread start/finish logs
wait for audio device before decoding