* qatar/master:
fate: Fix fate-ac3-fixed-encode for pre-ssse3 x86 machines
http: Pass the proper return code of net IO operations
http: Add 'post_data', a new option which sets custom HTTP post data
lavfi: amix: check active input count before calling request_samples
vp8: move block coeff arithcoder on stack.
mp3/ac3 probe: search for PES headers to prevent probing MPEG-PS as MP3.
Conflicts:
libavformat/ac3dec.c
libavformat/mp3dec.c
tests/fate/ac3.mak
Merged-by: Michael Niedermayer <michaelni@gmx.at>
This prevents gcc from assuming that contents of it may have changed
between calls to vp56_range_get_prob(), thus preventing countless (and
unnecessary) movs. Decoding of sintel trailer goes from (avg+SG) 9.796
+/- 0.003 to 9.635 +/- 0.010.
* qatar/master:
mpeg12: fixed parsing in some mpeg2 streams
Add SMPTE240M transfer characteristics flag.
mpegts: Some additional HDMV types and reg descriptors for mpegts
motionpixels: Clip YUV values after applying a gradient.
jpeg: handle progressive in second field of interlaced.
ituh263dec: Implement enough of Annex O (scalability) to fix a FPE.
h263: more strictly forbid frame size changes with frame-mt.
h264: additional protection against unsupported size/bitdepth changes.
tta: prevents overflows for 32bit integers in header.
configure: remove malloc_aligned.
vp8: update frame size changes on thread context switches.
snowdsp: explicitily state instruction size.
wmall: fix reconstructing audio with uncoded channels
WMAL cosmetics: fix indentation
gitignore: add Win32 library suffixes
Conflicts:
configure
libavcodec/h263dec.c
libavcodec/h264.c
libavcodec/ituh263dec.c
libavcodec/mjpegdec.c
libavcodec/wmalosslessdec.c
libavcodec/x86/snowdsp_mmx.c
libavformat/mpegts.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>
This properly synchronizes frame size changes between threads if
subsequent threads abort decoding before frame size is initialized, i.e.
it prevents the thread after that from ping-ponging back to the original
value.
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
* qatar/master:
rtpdec_asf: Set the no_resync_search option for the chained asf demuxer
asfdec: Add an option for not searching for the packet markers
cosmetics: Clean up the tiffenc pix_fmts declaration to match the style of others
cosmetics: Align codec declarations
cosmetics: Convert mimic.c to utf-8
avconv: remove an unused function parameter.
avconv: remove now pointless variables.
avconv: drop support for building without libavfilter.
nellymoserenc: fix crash due to memsetting the wrong area.
libavformat: Only require first packet to be known for audio/video streams
avplay: Don't try to scale timestamps if the tb isn't set
Conflicts:
Changelog
configure
ffmpeg.c
libavcodec/aacenc.c
libavcodec/bmpenc.c
libavcodec/dnxhddec.c
libavcodec/dnxhdenc.c
libavcodec/ffv1.c
libavcodec/flacenc.c
libavcodec/fraps.c
libavcodec/huffyuv.c
libavcodec/libopenjpegdec.c
libavcodec/mpeg12enc.c
libavcodec/mpeg4videodec.c
libavcodec/pamenc.c
libavcodec/pgssubdec.c
libavcodec/pngenc.c
libavcodec/qtrleenc.c
libavcodec/rawdec.c
libavcodec/sgienc.c
libavcodec/tiffenc.c
libavcodec/v210dec.c
libavcodec/wmv2dec.c
libavformat/utils.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Also break some long lines, remove codec function placeholder comments
and add spaces in sample/pixel format lists.
Signed-off-by: Martin Storsjö <martin@martin.st>
* qatar/master:
avc: Add a function for converting mp4 style extradata to annex b
pthread: free progress if buffer allocation failed.
lavc/avconv: support changing frame sizes in codecs with frame mt.
libavformat: Document who sets the AVStream.id field
utvideo: mark output picture as keyframe.
sunrast: Add support for negative linesize.
vp8: fix update_lf_deltas in libavcodec/vp8.c
ralf: read Huffman code lengths without GetBitContext
Conflicts:
ffmpeg.c
libavcodec/sunrastenc.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>
lf_delta.ref[i] and lf_delta.mode[i] were incorrectly reset to 0 if
specific delta value was not updated. Fixed to keep the previous value
if flag indicates that element in question is not updated.
Signed-off-by: Janne Salonen <jsalonen@google.com>
Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>
* qatar/master: (27 commits)
avconv: free packet in write_frame() when discarding due to frame number limit
FATE: use +/- flag option syntax for vp8 emu-edge tests
lavf: make av_interleave_packet_per_dts() private.
lavf: deprecate av_read_packet().
oggdec: output correct timestamps for Vorbis
avconv: pass input stream timestamps to audio encoders
lavc: shrink encoded audio packet size after encoding.
xa: set correct bit rate
xa: do not set bit_rate, block_align, or bits_per_coded_sample
xa: fix end-of-file handling
xa: fix timestamp calculation
bink: fix typo in FFALIGN() argument
bink: align plane width to 8 when calculating bundle sizes
doc: pass -Idoc texi2html and texi2pod
doc: texi2pod: add -I flag
movenc: Add a min_frag_duration option
rtsp: Set the default delay to 0.1 s for the RTSP/SDP/RTP demuxers
libavformat: Set the default for the max_delay option to -1
Generate manpages for AV{Format,Codec}Context AVOptions.
doc/avconv: remove entries for AVOptions.
...
Conflicts:
doc/Makefile
doc/ffmpeg.texi
doc/muxers.texi
ffmpeg.c
libavcodec/Makefile
libavcodec/options.c
libavcodec/vp8.c
libavformat/options.c
tests/fate/demux.mak
tests/ref/fate/truemotion1-15
tests/ref/fate/truemotion1-24
Merged-by: Michael Niedermayer <michaelni@gmx.at>
This change avoids accessing the segment map of the previous frame if
segmentation is not enabled for the current frame. The caller of
decode_mb_mode() only calls ff_thread_await_progress() on the reference
segmentation index array if segmentation is enabled, so Chromium's TSAN
will report a race when accessing this data while segmentation is not
enabled.
Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>
* qatar/master:
swscale: make yuv2yuv1 use named registers.
h264: mark h264_idct_add8_10 with number of XMM registers.
swscale: fix V plane memory location in bilinear/unscaled RGB/YUYV case.
vp8: always update next_framep[] before returning from decode_frame().
avconv: estimate next_dts from framerate if it is set.
avconv: better next_dts usage.
avconv: rename InputStream.pts to last_dts.
avconv: reduce overloading for InputStream.pts.
avconv: rename InputStream.next_pts to next_dts.
avconv: rework -t handling for encoding.
avconv: set encoder timebase for subtitles.
pva-demux test: add -vn
swscale: K&R formatting cosmetics for SPARC code
apedec: allow the user to set the maximum number of output samples per call
apedec: do not unnecessarily zero output samples for mono frames
apedec: allocate a single flat buffer for decoded samples
apedec: use sizeof(field) instead of sizeof(type)
swscale: split C output functions into separate file.
swscale: Split C input functions into separate file.
bytestream: Add bytestream2 writing API.
The avconv changes are due to massive regressions and bugs not merged yet.
Conflicts:
ffmpeg.c
libavcodec/vp8.c
libswscale/swscale.c
libswscale/x86/swscale_template.c
tests/fate/demux.mak
tests/ref/lavf/asf
tests/ref/lavf/avi
tests/ref/lavf/mkv
tests/ref/lavf/mpg
tests/ref/lavf/nut
tests/ref/lavf/ogg
tests/ref/lavf/rm
tests/ref/lavf/ts
tests/ref/seek/lavf_avi
tests/ref/seek/lavf_mkv
tests/ref/seek/lavf_rm
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Also slightly move around code not allocate a new frame if we won't
decode it. This prevents us from putting undecoded frames in frame
pointers, which (in mt decoding) other threads will use and wait on
as references, causing a deadlock (if we skipped decoding) or a crash
(if we didn't initialized next_framep[] at all).
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
* qatar/master:
Revert "v210enc: use FFALIGN()"
doxygen: Do not include license boilerplates in Doxygen comment blocks.
avplay: reset decoder flush state when seeking
ape: skip packets with invalid size
ape: calculate final packet size instead of guessing
ape: stop reading after the last frame has been read
ape: return AVERROR_EOF instead of AVERROR(EIO) when demuxing is finished
ape: return error if seeking to the current packet fails in ape_read_packet()
avcodec: Clarify AVFrame member documentation.
v210dec: check for coded_frame allocation failure
v210enc: use stride as it is already calculated
v210enc: use FFALIGN()
v210enc: return proper AVERROR codes instead of -1
v210enc: do not set coded_frame->key_frame
v210enc: check for coded_frame allocation failure
drawtext: add 'fix_bounds' option on coords fixing
drawtext: fix text_{w, h} expression vars
drawtext: add missing braces around an if() block.
Conflicts:
libavcodec/arm/vp8.h
libavcodec/arm/vp8dsp_init_arm.c
libavcodec/v210dec.c
libavfilter/vf_drawtext.c
libavformat/ape.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>
This reworks the frame skipping code such that the reference
buffers are still updated according to the header.
However it also ensures that the current frame will not end
up in any reference buffer.
Also fixes a hang with frame-multithreading, probably because
get_buffer was already called and would have reset the progress,
however the frame could remain in framep due to the missing update
(or it could be assigned to next_framep and a skip_frame skip would
then write it into framep - there might be even more failure modes).
Sample might become available at samples/nsv/vp8.nsv
Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>
* qatar/master:
aac_latm: reconfigure decoder on audio specific config changes
latmdec: fix audio specific config parsing
Add avcodec_decode_audio4().
avcodec: change number of plane pointers from 4 to 8 at next major bump.
Update developers documentation with coding conventions.
svq1dec: avoid undefined get_bits(0) call
ARM: h264dsp_neon cosmetics
ARM: make some NEON macros reusable
Do not memcpy raw video frames when using null muxer
fate: update asf seektest
vp8: flush buffers on size changes.
doc: improve general documentation for MacOSX
asf: use packet dts as approximation of pts
asf: do not call av_read_frame
rtsp: Initialize the media_type_mask in the rtp guessing demuxer
Cleaned up alacenc.c
Conflicts:
doc/APIchanges
doc/developer.texi
libavcodec/8svx.c
libavcodec/aacdec.c
libavcodec/ac3dec.c
libavcodec/avcodec.h
libavcodec/nellymoserdec.c
libavcodec/tta.c
libavcodec/utils.c
libavcodec/version.h
libavcodec/wmadec.c
libavformat/asfdec.c
tests/ref/seek/lavf_asf
Merged-by: Michael Niedermayer <michaelni@gmx.at>
A new field, AVCodecContext.internal is used to hold a new struct
AVCodecInternal, which has private fields that are not codec-specific and are
used by general libavcodec functions.
Moved internal_buffer, internal_buffer_count, and is_copy.
* qatar/master: (51 commits)
cin audio: use sign_extend() instead of casting to int16_t
cin audio: restructure decoding loop to avoid a separate counter variable
cin audio: use local variable for delta value
cin audio: remove unneeded cast from void*
cin audio: validate the channel count
cin audio: remove unneeded AVCodecContext pointer from CinAudioContext
dsicin: fix several audio-related fields in the CIN demuxer
flacdec: use av_get_bytes_per_sample() to get sample size
dca: handle errors from dca_decode_block()
dca: return error if the frame header is invalid
dca: return proper error codes instead of -1
utvideo: handle empty Huffman trees
binkaudio: change short to int16_t
binkaudio: only decode one block at a time.
binkaudio: store interleaved overlap samples in BinkAudioContext.
binkaudio: pre-calculate quantization factors
binkaudio: add some buffer overread checks.
atrac3: support float or int16 output using request_sample_fmt
atrac3: add CODEC_CAP_SUBFRAMES capability
atrac3: return appropriate error codes instead of -1
...
Conflicts:
libavcodec/atrac1.c
libavcodec/dca.c
libavformat/mov.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>
* qatar/master: (35 commits)
flvdec: Do not call parse_keyframes_index with a NULL stream
libspeexdec: include system headers before local headers
libspeexdec: return meaningful error codes
libspeexdec: cosmetics: reindent
libspeexdec: decode one frame at a time.
swscale: fix signed shift overflows in ff_yuv2rgb_c_init_tables()
Move timefilter code from lavf to lavd.
mov: add support for hdvd and pgapmetadata atoms
mov: rename function _stik, some indentation cosmetics
mov: rename function _int8 to remove ambiguity, some indentation cosmetics
mov: parse the gnre atom
mp3on4: check for allocation failures in decode_init_mp3on4()
mp3on4: create a separate flush function for MP3onMP4.
mp3on4: ensure that the frame channel count does not exceed the codec channel count.
mp3on4: set channel layout
mp3on4: fix the output channel order
mp3on4: allocate temp buffer with av_malloc() instead of on the stack.
mp3on4: copy MPADSPContext from first context to all contexts.
fmtconvert: port float_to_int16_interleave() 2-channel x86 inline asm to yasm
fmtconvert: port int32_to_float_fmul_scalar() x86 inline asm to yasm
...
Conflicts:
libavcodec/arm/h264dsp_init_arm.c
libavcodec/h264.c
libavcodec/h264.h
libavcodec/h264_cabac.c
libavcodec/h264_cavlc.c
libavcodec/h264_ps.c
libavcodec/h264dsp_template.c
libavcodec/h264idct_template.c
libavcodec/h264pred.c
libavcodec/h264pred_template.c
libavcodec/x86/h264dsp_mmx.c
libavdevice/Makefile
libavdevice/jack_audio.c
libavformat/Makefile
libavformat/flvdec.c
libavformat/flvenc.c
libavutil/pixfmt.h
libswscale/utils.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Associate segmentation_map[] with reference frame, rather than
decoding instance. This fixes cases where the map would be free()'ed
on e.g. a size change in one thread, whereas the other thread was
still accessing it. Also, it fixes cases where threads overwrite data
that is still being referenced by the previous thread, who thinks that
it's part of the frame previously decoded by the next thread.
* qatar/master:
prores: get correct size for coded V plane if alpha is present
prores: do not set pixel format on codec init
pthread: prevent updating AVCodecContext from itself in frame_thread_free
pthread: copy coded frame dimensions in update_context_from_thread
vp8: prevent read from uninitialized memory in decode_mvs
vp8: force reallocation in update_thread_context after frame size change
vp8: fix return value if update_dimensions fails
matroskadec: fix out of bounds write
adpcmdec: calculate actual number of output samples for each decoder.
adpcmdec: check remaining buffer size before decoding next block in the ADPCM IMA WAV decoder.
adpcmdec: do not terminate early in ADPCM IMA Duck DK3 decoder.
adpcmdec: remove unneeded buf_size==0 check.
adpcmdec: remove unneeded zeroing of *data_size
dnxhdenc: fixed signed multiplication overflow
Conflicts:
tests/ref/fate/prores-alpha
tests/ref/fate/truemotion1-24
Merged-by: Michael Niedermayer <michaelni@gmx.at>
* qatar/master:
lavf: fix signed overflow in avformat_find_stream_info()
vp8: fix signed overflows
motion_est: fix some signed overflows
dca: fix signed overflow in shift
aacdec: fix undefined shifts
bink: Check for various out of bound writes
bink: Check for out of bound writes when building tree
put_bits: fix invalid shift by 32 in flush_put_bits()
Conflicts:
libavcodec/bink.c
libavformat/utils.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>
In addition to avoiding undefined behaviour, an unsigned type
makes more sense for packing multiple 8-bit values.
Signed-off-by: Mans Rullgard <mans@mansr.com>
* qatar/master:
mxfdec: Include FF_INPUT_BUFFER_PADDING_SIZE when allocating extradata.
H.264: tweak some other x86 asm for Atom
probe: Fix insane flow control.
mpegts: remove invalid error check
s302m: use nondeprecated audio sample format API
lavc: use designated initialisers for all codecs.
x86: cabac: add operand size suffixes missing from 6c32576
Conflicts:
libavcodec/ac3enc_float.c
libavcodec/flacenc.c
libavcodec/frwu.c
libavcodec/pictordec.c
libavcodec/qtrleenc.c
libavcodec/v210enc.c
libavcodec/wmv2dec.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>
* qatar/master: (36 commits)
ARM: allow unaligned buffer in fixed-point NEON FFT4
fate: test more FFT etc sizes
dca: set AVCodecContext frame_size for DTS audio
YASM: Shut up unused variable compiler warning with --disable-yasm.
x86_32: Fix build on x86_32 with --disable-yasm.
iirfilter: add fate test
doxygen: Add qmul docs.
ogg: propagate return values and return more meaningful error values
H.264: fix overreads of qscale_table
Remove unused static tables and static inline functions.
eval: clear Parser instances before using
dct-test: remove 'ref' function pointer from tables
build: Remove deleted 'check' target from .PHONY list.
oggdec: Abort Ogg header parsing when encountering a data packet.
Add LGPL license boilerplate to files lacking it.
mxfenc: small typo fix
doxygen: Fix documentation for some VP8 functions.
sha: use AV_RB32() instead of assuming buffer can be cast to uint32_t*
des: allow unaligned input and output buffers
aes: allow unaligned input and output buffers
...
Conflicts:
libavcodec/dct-test.c
libavcodec/libvpxenc.c
libavcodec/x86/dsputil_mmx.c
libavcodec/x86/h264_qpel_mmx.c
libavfilter/x86/gradfun.c
libavformat/oggdec.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>
* qatar/master: (40 commits)
H.264: template left MB handling
H.264: faster fill_decode_caches
H.264: faster write_back_*
H.264: faster fill_filter_caches
H.264: make filter_mb_fast support the case of unavailable top mb
Do not include log.h in avutil.h
Do not include pixfmt.h in avutil.h
Do not include rational.h in avutil.h
Do not include mathematics.h in avutil.h
Do not include intfloat_readwrite.h in avutil.h
Remove return statements following infinite loops without break
RTSP: Doxygen comment cleanup
doxygen: Escape '\' in Doxygen documentation.
md5: cosmetics
md5: use AV_WL32 to write result
md5: add fate test
md5: include correct headers
md5: fix test program
doxygen: Drop array size declarations from Doxygen parameter names.
doxygen: Fix parameter names to match the function prototypes.
...
Conflicts:
libavcodec/x86/dsputil_mmx.c
libavformat/flvenc.c
libavformat/oggenc.c
libavformat/wtv.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>
* qatar/master:
vf_drawtext: Replace FFmpeg by Libav in license boilerplate.
mpegaudiodec: remove unusued code and variables
improved 'edts' atom writing support
mpegaudio: clean up compute_antialias() definition
vp8: fix segmentation race during frame-threading.
Merged-by: Michael Niedermayer <michaelni@gmx.at>
* qatar/master:
ARM: enable UAL syntax in asm.S
v4l2: don't leak video standard string on error.
swscale: Remove disabled code.
avfilter: Surround function only used in debug mode by appropriate #ifdef.
vf_crop: Replace #ifdef DEBUG + av_log() by av_dlog().
build: remove BUILD_ROOT variable
vp8: use av_clip_uintp2() where possible
Merged-by: Michael Niedermayer <michaelni@gmx.at>
* qatar/master:
swscale: properly inline bits/endianness in yuv2yuvX16inC().
(We didnt pull the bug) swscale: fix clipping of 9/10bit YUV420P.
Add av_clip_uintp2() function
(our patch / duplicate) dfa: fix buffer overflow checks to avoid integer overflows.
(our patch / duplicate) movenc: always write esds descriptor length using 4 bytes.
(our patch / duplicate) ffmpeg: use parse_number_and_die() when it makes sense
(No thanks) ffmpeg: get rid of the 'q' key schizofrenia
Merged-by: Michael Niedermayer <michaelni@gmx.at>
This patch lets e.g. dsputil_init chose dsp functions with respect to
the bit depth to decode. The naming scheme of bit depth dependent
functions is <base name>_<bit depth>[_<prefix>] (i.e. the old
clear_blocks_c is now named clear_blocks_8_c).
Note: Some of the functions for high bit depth is not dependent on the
bit depth, but only on the pixel size. This leaves some room for
optimizing binary size.
Preparatory patch for high bit depth h264 decoding support.
Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>
* qatar/master:
vp8: frame-multithreading.
Duplicate Replace deprecated FF_*_TYPE symbols with AV_PICTURE_TYPE_*.
Duplicate Replace deprecated av_get_pict_type_char() with av_get_picture_type_char().
Bug spoted&removed in last merge: dpx: Do not use DPX encoder for decoding.
Conflicts:
ffmpeg.c
ffplay.c
libavcodec/h264.c
libavcodec/mpeg12.c
libavcodec/mpeg4videodec.c
libavcodec/mpegvideo.c
libavcodec/mpegvideo_enc.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>
This patch lets e.g. dsputil_init chose dsp functions with respect to
the bit depth to decode. The naming scheme of bit depth dependent
functions is <base name>_<bit depth>[_<prefix>] (i.e. the old
clear_blocks_c is now named clear_blocks_8_c).
Note: Some of the functions for high bit depth is not dependent on the
bit depth, but only on the pixel size. This leaves some room for
optimizing binary size.
Preparatory patch for high bit depth h264 decoding support.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
* newdev/master:
mov: set audio service type for AC-3 from bitstream mode in the 'dac3' atom.
Get audio_service_type for AC-3 based on bitstream mode in the AC-3 parser and decoder, and vice-versa for the AC-3 encoder.
Use audio_service_type to set stream disposition.
Add APIchanges entry for audio_service_type.
Add audio_service_type field to AVCodecContext for encoding and reporting of the service type in the audio bitstream.
configure: in check_ld, place new -l flags before existing ones
support @heading, @subheading, @subsubheading, and @subsubsection in texi2pod.pl
doc: update build system documentation
aacenc: indentation
aacenc: fix the side calculation in search_for_ms
vp8.c: rename EDGE_* to VP8_EDGE_*.
Conflicts:
doc/APIchanges
libavcodec/avcodec.h
libavcodec/version.h
libavcodec/vp8.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>
It is pretty hopeless that other considerable projects will adopt
libavutil alone in other projects. Projects that need small footprint
are better off with more specialized libraries such as gnulib or rather
just copy the necessary parts that they need. With this in mind, nobody
is helped by having libavutil and libavcore split. In order to ease
maintenance inside and around FFmpeg and to reduce confusion where to
put common code, avcore's functionality is merged (back) to avutil.
Signed-off-by: Reinhard Tartler <siretart@tauware.de>
Do not emulate larger edges than we will actually use for this round of
MC. Decoding goes from avg+SE 29.972+/-0.023sec to 29.856+/-0.023, i.e.
0.12sec or ~0.4% faster.
correct mb_xy to use mb_width.
tighten allocations.
reduce the amount of zeroing.
Originally committed as revision 24760 to svn://svn.ffmpeg.org/ffmpeg/trunk
Create a custom table for VP5/6/8's renorm to avoid depending on H.264's.
Saves one instruction in the arithmetic decoder as well.
Originally committed as revision 24701 to svn://svn.ffmpeg.org/ffmpeg/trunk
A lot of the time the DC block is empty: don't do the WHT in this case.
A lot of the rest of the time, there's only one coefficient: make a special
DC-only transform for that case.
When the block is empty, don't incorrectly mark luma DCT blocks as having DC
coefficients.
Originally committed as revision 24670 to svn://svn.ffmpeg.org/ffmpeg/trunk
Lets us do the zeroing in asm instead of C.
Also makes it consistent with the way the regular iDCT code does it.
Originally committed as revision 24668 to svn://svn.ffmpeg.org/ffmpeg/trunk
