November 2014 - FFmpeg-trac - lists.ffmpeg.org

#3409(undetermined:new): Impossible to transcode full range RGB videos with libx264, and keep full range + proper colors
by FFmpeg 15 Jan '22

15 Jan '22

#3409: Impossible to transcode full range RGB videos with libx264, and keep full range + proper colors -------------------------------------+------------------------------------- Reporter: mzso | Type: defect Status: new | Priority: normal Component: | Version: undetermined | unspecified Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- I encountered this while trying to transcode screencasted videos with fraps or ut-video streams. When using yuv444p pixel format I get washed out, too light videos. "-color_range" has no affect. People suggested: "-vf colormatrix=bt601:bt709" But it also doesn't have an affect. x264 itself has issues with RGB full range videos, if I use i444 with it I also get improper output. But if I use "--output-csp rgb" it succeds in encoding a proper output file, though with a large file size. I can't even achieve this with ffmpeg because it doesn't let me use RGB with libx264: "Incompatible pixel format 'rgb24' for codec 'libx264', auto-selecting format 'yuv444p'" -- Ticket URL: <https://trac.ffmpeg.org/ticket/3409> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker

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#4024(avcodec:new): VP9 crash
by FFmpeg 02 Nov '21

02 Nov '21

#4024: VP9 crash ----------------------------------+-------------------------------------- Reporter: kyh96403 | Type: defect Status: new | Priority: normal Component: avcodec | Version: git-master Keywords: vp9 | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | ----------------------------------+-------------------------------------- When decoding some webm file(video codec is vp9), crash is occur. -- Ticket URL: <https://trac.ffmpeg.org/ticket/4024> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker

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#4048(avformat:new): segment: Handle WebVTT as per HLS spec
by FFmpeg 01 Nov '21

01 Nov '21

#4048: segment: Handle WebVTT as per HLS spec ----------------------------------+--------------------------------------- Reporter: 11rcombs | Type: enhancement Status: new | Priority: normal Component: avformat | Version: git-master Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | ----------------------------------+--------------------------------------- As per the [http://tools.ietf.org/html/draft-pantos-http-live- streaming-13#section-4 HLS spec]: {{{ Subtitle segments MUST be formatted as WebVTT [WebVTT] files. Each subtitle segment MUST contain all subtitle cues that are intended to be displayed during the period indicated by the segment EXTINF duration. The start time offset and end time offset of each cue MUST indicate the total display time for that cue, even if that time range extends beyond the EXTINF duration. A WebVTT segment MAY contain no cues; this indicates that no subtitles are to be displayed during that period. }}} This means that the segment (or HLS) muxer needs to handle two particular cases, when muxing WebVTT for HLS: 1. No frames exist during a segment's duration, so a blank segment should be written. 2. A frame spans two or more different segments, so it should be written in all of them. This behavior could be triggered by an option, or automatically when the underlying format is WebVTT. Relatedly, the WebVTT muxer should provide an option to write the X -TIMESTAMP-MAP header for HLS synchronization. -- Ticket URL: <https://trac.ffmpeg.org/ticket/4048> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker

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#3389(ffmpeg:new): Feature Request - Isolate and normalize video content
by FFmpeg 29 Aug '21

29 Aug '21

#3389: Feature Request - Isolate and normalize video content -------------------------------------+------------------------------------- Reporter: Rafajafar | Type: Status: new | enhancement Component: ffmpeg | Priority: wish Keywords: feature | Version: request normalize video | unspecified Blocking: | Blocked By: Analyzed by developer: 0 | Reproduced by developer: 0 -------------------------------------+------------------------------------- Hey, I have an interesting problem and I'm solving it with OpenCV. It's be great if the solution could come straight from ffmpeg, though! I need to: 1) cropdetect 2) crop surrounding borders from a video 3) resize video to normalize its dimensions In other words, all I want is one command that will detect the frame-by- frame borders and in the same step, crop it, and also resize it. And I want this done for the entire video, not a single frame. It's gotta be possible, right? The applications are very useful in video analysis. I've spoken to colleagues of mine and they are doing this manually themselves. It would be great to be able to work this feature into the automation surrounding ffmpeg in our tools. My personal application, for instance, is in detecting videos that are similar using content perceptual hashing. Another colleague of mine works for the Center for Missing and Exploited Children. He does similar work, but with pHashing. I can see applications for ContentID type systems across the board. I'm sure this is a low on the totem pole request, but if you have any spare cycles, this would really rock in the world of computer vision and video analysis! Thanks for your consideration, --Collin -- Ticket URL: <https://trac.ffmpeg.org/ticket/3389> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker

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#3692(avcodec:new): dpx samples (possibly broken) look broken with FFmpeg, work fine with ImageMagick
by FFmpeg 07 May '21

07 May '21

#3692: dpx samples (possibly broken) look broken with FFmpeg, work fine with ImageMagick --------------------------------------+--------------------------------- Reporter: cehoyos | Owner: Type: defect | Status: new Priority: normal | Component: avcodec Version: git-master | Keywords: dpx Blocked By: | Blocking: Reproduced by developer: 0 | Analyzed by developer: 0 --------------------------------------+--------------------------------- http://www.simplesystems.org/users/bfriesen/dpx/ contains three dpx samples, one (16 bit) looks ugly with FFmpeg, ImageMagick and GraphicsMagick, the other two (8 bit) only look broken with FFmpeg. {{{ $ ffmpeg -i DLAD_8b_1c_big.dpx ffmpeg version N-63624-g4ba8560 Copyright (c) 2000-2014 the FFmpeg developers built on May 31 2014 12:24:49 with gcc 4.7 (SUSE Linux) configuration: --enable-gpl libavutil 52. 87.100 / 52. 87.100 libavcodec 55. 65.100 / 55. 65.100 libavformat 55. 42.100 / 55. 42.100 libavdevice 55. 13.101 / 55. 13.101 libavfilter 4. 5.100 / 4. 5.100 libswscale 2. 6.100 / 2. 6.100 libswresample 0. 19.100 / 0. 19.100 libpostproc 52. 3.100 / 52. 3.100 Input #0, image2, from 'DLAD_8b_1c_big.dpx': Duration: 00:00:00.04, start: 0.000000, bitrate: N/A Stream #0:0: Video: dpx, gray, 255x185 [SAR 1:1 DAR 51:37], 25 tbr, 25 tbn, 25 tbc At least one output file must be specified }}} {{{ $ ffmpeg -i DLAD_8b_3c_big.dpx ffmpeg version N-63624-g4ba8560 Copyright (c) 2000-2014 the FFmpeg developers built on May 31 2014 12:24:49 with gcc 4.7 (SUSE Linux) configuration: --enable-gpl libavutil 52. 87.100 / 52. 87.100 libavcodec 55. 65.100 / 55. 65.100 libavformat 55. 42.100 / 55. 42.100 libavdevice 55. 13.101 / 55. 13.101 libavfilter 4. 5.100 / 4. 5.100 libswscale 2. 6.100 / 2. 6.100 libswresample 0. 19.100 / 0. 19.100 libpostproc 52. 3.100 / 52. 3.100 Input #0, image2, from 'DLAD_8b_3c_big.dpx': Duration: 00:00:00.04, start: 0.000000, bitrate: N/A Stream #0:0: Video: dpx, rgb24, 255x185 [SAR 1:1 DAR 51:37], 25 tbr, 25 tbn, 25 tbc At least one output file must be specified }}} -- Ticket URL: <https://trac.ffmpeg.org/ticket/3692> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker

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#3785(undetermined:new): SWSCALE: in_range, in_color_matrix, out_range, out_color_matrix incorrect
by FFmpeg 24 Apr '21

24 Apr '21

#3785: SWSCALE: in_range, in_color_matrix, out_range, out_color_matrix incorrect -------------------------------------+------------------------------------- Reporter: troy_s | Type: defect Status: new | Priority: normal Component: | Version: git- undetermined | master Keywords: | Blocked By: colormanagement colorspace 709 | Reproduced by developer: 0 601 | Blocking: | Analyzed by developer: 0 | -------------------------------------+------------------------------------- '''Summary of the bug''': Seems that swscale is still sadly mangling RGB to YCbCr and vice versa transforms. Disabled all ASM speedups to avoid code path issues, as were previously hard coded to 601 coefficents etc. '''How to reproduce''': Encode a test chart and check values. Test chart available from http://www .belle-nuit.com/test-chart. '''Expected versus Results''': BT.709 and sRGB share identical luminance coefficients. An sRGB image, encoded at full range using BT.709 primaries should decode to a perfect 1:1 regarding RGB values, compression notwithstanding. Sampling the upper row of colors using the provided test chart, we can see some issues with the encoding / decoding step, when using FFPLAY with the corresponding scale commands. For example, an encode using {{{ ./ffmpeg -loop 1 -i ~/Downloads/testchart.tif -t 3 -c:v h264 -vf "scale=in_range=full:in_color_matrix=bt709:out_range=full:out_color_matrix=bt709" out709-full.mp4 }}} Should produce a perfect 1:1 when played back with {{{ ./ffplay -vf "scale=in_range=full:in_color_matrix=bt709:out_range=full:out_color_matrix=bt709" out709-full.mp4 }}} When we sample the sRGB / 709 values using an image editor, the top row should result in RGB values as follows: {{{ Name R G B Yellow: 180 180 16 Cyan: 16 180 180 Magenta: 180 16 180 Green: 16 180 16 Red: 180 16 16 Blue: 16 16 180 }}} Given that 709 and sRGB share identical primaries, and broadcast scaling is set to full range, there should be a perfect 1:1 result with the values. However, what we find with playback via the ffmpeg command set with proper values is: {{{ Name R G B Yellow: 179 190 22 Cyan: 31 197 180 Magenta: 167 0 176 Green: 30 209 21 Red: 166 0 19 Blue: 17 5 173 }}} There appears to be breakage with regard to the application of the coefficients, as well as possibly misinterpretation of the full range settings. The are some transforms that yield vaguely close values. However, these suffer from quantization issues where no such should occur. It would seem that all transformations are likely being performed at the relative bit depth for performance. Sadly, this corrupts the values quite significantly. {{{ ./ffmpeg -loop 1 -i ~/Downloads/testchart.tif -t 3 -c:v h264 -vf "scale=in_range=full:in_color_matrix=bt601:out_range=full:out_color_matrix=bt601" out601-full.mp4 }}} The following, despite being 601 coefficients, should yield perfect 1:1 with RGB values (RGB being a relative color space) but quantization issues again result. {{{ ./ffplay -vf "scale=in_range=full:in_color_matrix=bt601:out_range=full:out_color_matrix=bt601" out601-full.mp4 }}} Further testing of the in_range and out_range specifics will be conducted when the basic color coefficients issue is corrected. '''Conclusion''': Some mangling is still present in the color handling in FFMPEG. Quantization issues can likely be expected until a float (likely non- realtime) option is introduced for higher quality frame by frame encoding / decoding. However, even with quantization issues, the encoding / decoding coefficients are not responding / respected in correct fashion for 709 to 709 (1:1 with sRGB content). -- Ticket URL: <https://trac.ffmpeg.org/ticket/3785> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker

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#3794(swscale:new): SWSCALE: Quantization Errors in Y Studio Range
by FFmpeg 19 Apr '21

19 Apr '21

#3794: SWSCALE: Quantization Errors in Y Studio Range ------------------------------------+-------------------------------------- Reporter: troy_s | Type: defect Status: new | Priority: normal Component: swscale | Version: git-master Keywords: 709 Y luma | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | ------------------------------------+-------------------------------------- Summary of the bug: It appears FFMPEG has some +/- single unit quantization errors in the YCbCr transform. How to reproduce: Generate a raw YCbCr image and diff against theoretically correct values. {{{ ./ffmpeg -i ~/Documents/FFMPEG\ Color\ Research/ARIB_STD-B28.png -pix_fmt yuv444p -vcodec rawvideo -f rawvideo -vf scale="in_range=full:in_color_matrix=bt709:out_range=full:out_color_matrix=bt709" test.yuv ffmpeg version N-64815-gb53bdae Copyright (c) 2000-2014 the FFmpeg developers built on Jul 19 2014 16:33:49 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1) configuration: --enable-gpl --enable-libx264 --disable-asm libavutil 52. 92.101 / 52. 92.101 libavcodec 55. 69.100 / 55. 69.100 libavformat 55. 48.101 / 55. 48.101 libavdevice 55. 13.102 / 55. 13.102 libavfilter 4. 11.102 / 4. 11.102 libswscale 2. 6.100 / 2. 6.100 libswresample 0. 19.100 / 0. 19.100 libpostproc 52. 3.100 / 52. 3.100 Input #0, image2, from '/home/aphorism/Documents/FFMPEG Color Research/ARIB_STD-B28.png': Duration: 00:00:00.04, start: 0.000000, bitrate: N/A Stream #0:0: Video: png, rgb24, 1920x1080 [SAR 2835:2835 DAR 16:9], 25 tbr, 25 tbn, 25 tbc Output #0, rawvideo, to 'test.yuv': Metadata: encoder : Lavf55.48.101 Stream #0:0: Video: rawvideo (444P / 0x50343434), yuv444p, 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 25 fps, 25 tbn, 25 tbc Metadata: encoder : Lavc55.69.100 rawvideo Stream mapping: Stream #0:0 -> #0:0 (png (native) -> rawvideo (native)) Press [q] to stop, [?] for help frame= 1 fps=0.0 q=0.0 Lsize= 6075kB time=00:00:00.04 bitrate=1244160.0kbits/s video:6075kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.000000% }}} Diff'd versions of the theoretically ideal values versus FFMPEG's output. Lowest red stripe is due to theoretical version preserving the -2% patch, and not relevant. -- Ticket URL: <https://trac.ffmpeg.org/ticket/3794> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker

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#3623(undetermined:new): Mixed results writing M4A metadata
by FFmpeg 15 Apr '21

15 Apr '21

#3623: Mixed results writing M4A metadata -------------------------------------+------------------------------------- Reporter: svnpenn | Type: defect Status: new | Priority: normal Component: | Version: undetermined | unspecified Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Given this file http://bitbucket.org/svnpenn/a/downloads/superuser.mp4 I am having mixed results writing metadata. For example these commands {{{ ffmpeg -i superuser.mp4 -c copy good.aac ffmpeg -i good.aac -c copy -bsf aac_adtstoasc -metadata title=Confetti \ -movflags faststart good.m4a }}} Will generate an M4A file that plays correctly with metadata that is recognized. However this command {{{ ffmpeg -i superuser.mp4 -c copy -vn -movflags faststart \ -metadata title=Confetti bad.m4a }}} Generates a file that plays correctly, but my player does not recognize the metadata. Note I also tried adding `-bsf aac_adtstoasc` to the bad command to no avail. How can I tweak the second command to get it working? Command-line output http://gist.github.com/svnpenn/82e7f7685084759c7483 Source question http://superuser.com/q/750627 -- Ticket URL: <https://trac.ffmpeg.org/ticket/3623> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker

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#3586(avcodec:new): [discrepancy with libav] avcodec_encode_video2 merges packet side data with the packet body
by FFmpeg 10 Apr '21

10 Apr '21

#3586: [discrepancy with libav] avcodec_encode_video2 merges packet side data with the packet body -------------------------------------+------------------------------------- Reporter: Lastique | Type: defect Status: new | Priority: normal Component: avcodec | Version: 2.2.1 Keywords: libav | Blocked By: avcodec_encode_video2 avpacket | Reproduced by developer: 0 av_packet_merge_side_data | Blocking: | Analyzed by developer: 0 | -------------------------------------+------------------------------------- We have an application which uses ffmpeg to encode video in h263. The application requests h263_mb_info side data by setting the "mb_info" option on the encoder context: {{{ av_opt_set_int(av_ctx, "mb_info", 1400, AV_OPT_SEARCH_CHILDREN) }}} Later we call avcodec_encode_video2() to encode frames. The problem is that ffmpeg avcodec_encode_video2() returns AVPackets with the encoded frame and some amount of junk at the end. From the source code I can see that the junk is actually the encoded side data (mb_info) appended to the h263 packet by av_packet_merge_side_data() which is called by avcodec_encode_video2(). This appended side data prevents the packets from being decoded by ffmpeg 2.2.1 (I tried both decoding through the API and ffplay). Decoding results in many messages such as: {{{ slice end not reached but screenspace end (399 left 019CE3, score= -7) concealing 88 DC, 88 AC, 88 MV errors in P frame }}} and corrupted image. This is also different from libav behavior. At least 9.x and 10.x versions don't merge side data into the packet body, and when using libav we don't have the decoding problem. Looking at the libavcodec code I don't really understand why the call to av_packet_merge_side_data() is needed. Side data, at least mb_info in case of h263, is not the part of the encoded media and thus should not be part of the packet body. Since the packet size (AVPacket::size) includes the appended side data, there is no way to obtain the size of the actual media. I suspect, av_packet_split_side_data() can be used to restore the original un-merged packet, but (a) it is not documented and (b) doing av_packet_merge_side_data() and av_packet_split_side_data() is a waste of memory and CPU (note: we pre-allocate packet data buffer to optimize performance). Therefore my preferred solution would be to remove the call to av_packet_merge_side_data() from avcodec_encode_video2(). If that call cannot be removed then what is the correct way to obtain the actual media from the merged packet? -- Ticket URL: <https://trac.ffmpeg.org/ticket/3586> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker

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#3516(undetermined:new): mjpeg: wrong colors (CMYK with subsampling)
by FFmpeg 22 Mar '21

22 Mar '21

#3516: mjpeg: wrong colors (CMYK with subsampling) -------------------------------------+------------------------------------- Reporter: ami_stuff | Owner: Type: defect | Status: new Priority: normal | Component: Version: | undetermined unspecified | Keywords: Blocked By: | Blocking: Reproduced by developer: 0 | Analyzed by developer: 0 -------------------------------------+------------------------------------- attached file decodes with wrong colors {{{ C:\>ffmpeg3 -i YCbCrK.jpg out.bmp ffmpeg version 2.2.git-0f714ab Copyright (c) 2000-2014 the FFmpeg developers built on Mar 31 2014 22:26:54 with gcc 4.6.2 (GCC) configuration: --disable-ffprobe --disable-pthreads --enable-gpl libavutil 52. 70.100 / 52. 70.100 libavcodec 55. 55.106 / 55. 55.106 libavformat 55. 36.100 / 55. 36.100 libavdevice 55. 11.100 / 55. 11.100 libavfilter 4. 3.100 / 4. 3.100 libswscale 2. 5.102 / 2. 5.102 libswresample 0. 18.100 / 0. 18.100 libpostproc 52. 3.100 / 52. 3.100 [mjpeg @ 01d76580] Warning: not compiled with thread support, using thread emula tion Input #0, image2, from 'YCbCrK.jpg': Duration: 00:00:00.04, start: 0.000000, bitrate: N/A Stream #0:0: Video: mjpeg, yuva420p(pc), 1024x768, 25 tbr, 25 tbn, 25 tbc [bmp @ 01d78c00] Warning: not compiled with thread support, using thread emulati on [mjpeg @ 01d76580] Warning: not compiled with thread support, using thread emula tion Output #0, image2, to 'out.bmp': Metadata: encoder : Lavf55.36.100 Stream #0:0: Video: bmp, bgra, 1024x768, q=2-31, 200 kb/s, 90k tbn, 25 tbc Stream mapping: Stream #0:0 -> #0:0 (mjpeg -> bmp) Press [q] to stop, [?] for help frame= 1 fps=0.0 q=0.0 Lsize=N/A time=00:00:00.04 bitrate=N/A video:3072kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 586396112781312.000000% }}} -- Ticket URL: <https://trac.ffmpeg.org/ticket/3516> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker

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