lavfi/aevalsrc: duplicate last expression for the missing channels

Use last expression for the missing channel expressions in case the
channel layout was specified. Enhance flexibility.
lavfi: add aeval filter
lavfi: rename asrc_aevalsrc.c to aeval.c

The file now contains both source and filter, the new name looks more
appropriate.
Merge commit '058d5f2feb730846f22c1812e433f92f670ad751'

* commit '058d5f2feb730846f22c1812e433f92f670ad751':
  mjpegenc: do not pass MpegEncContext to ff_mjpeg_encode_picture_header()

Conflicts:
	libavcodec/mjpegenc.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '3360ad995530ea6967b1e83981b4aa8240fbb0ed'

* commit '3360ad995530ea6967b1e83981b4aa8240fbb0ed':
  mjpegenc: do not pass MpegEncContext to ff_mjpeg_encode_picture_trailer()

Conflicts:
	libavcodec/ljpegenc.c
	libavcodec/mjpegenc.c
	libavcodec/mjpegenc.h

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '86eb2eaac629909d6ee4067c6f1e485a4e70473d'

* commit '86eb2eaac629909d6ee4067c6f1e485a4e70473d':
  mjpegenc: do not pass MpegEncContext to ff_mjpeg_encode_dc()

Conflicts:
	libavcodec/mjpegenc.h

Merged-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/ljpegenc: fix mem allocation failure return code encode_picture_lossless()

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/mjpegenc: make escape_FF() non static

This will be used by ljpeg

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/mjpegenc: move end padding/alignment to ff_mjpeg_escape_FF()

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/ljpegenc: Dont use ff_mjpeg_encode_stuffing()

This avoids a use of MpegEncContext

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '24abd806ea0cfb0d988d2f0044eac79cff12918c'

* commit '24abd806ea0cfb0d988d2f0044eac79cff12918c':
  ljpegenc: deMpegEncContextize

Conflicts:
	libavcodec/ljpegenc.c
	libavcodec/mpegvideo.h
	libavcodec/mpegvideo_enc.c
	tests/ref/vsynth/vsynth1-ljpeg
	tests/ref/vsynth/vsynth2-ljpeg

Merged-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/mjpegenc: fix and use lossless flag in ff_mjpeg_encode_picture_header()

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '72c0b8f724a71d2784aecad0e5221e7ab6206371'

* commit '72c0b8f724a71d2784aecad0e5221e7ab6206371':
  ljpeg: remove a commented-out line

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '0cdbc4d39394965bd8712395b19160da8f3fe144'

* commit '0cdbc4d39394965bd8712395b19160da8f3fe144':
  ljpegenc: rename the encoding function.

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit 'daffed3b173c59d64907747bf3309e98a8974f4e'

* commit 'daffed3b173c59d64907747bf3309e98a8974f4e':
  ljpegenc: accept bgr24 instead of bgra

Conflicts:
	libavcodec/ljpegenc.c
	libavcodec/mjpegenc.c

Only whitespace merged, we continue to support both formats

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit 'fa4476815d0d27996eb199452f2cdbfccdd244a5'

* commit 'fa4476815d0d27996eb199452f2cdbfccdd244a5':
  ljpegenc: split bgr encoding into a separate function

Conflicts:
	libavcodec/ljpegenc.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit 'b73a8922d818c7f909855557718d4c3bfacbd92d'

* commit 'b73a8922d818c7f909855557718d4c3bfacbd92d':
  ljpegenc: split yuv encoding into a separate function

Conflicts:
	libavcodec/ljpegenc.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit 'f51e3a1971045c7ed0c3d9d29d3254a4d940198e'

* commit 'f51e3a1971045c7ed0c3d9d29d3254a4d940198e':
  webp: do not call av_frame_free() on the user-provided frame

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge remote-tracking branch 'qatar/master'

* qatar/master:
  webp: add a special case for a huffman table with only 1 symbol

Merged-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/mjpegenc/ff_mjpeg_escape_FF: remove unused variable

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>