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January 2024

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#10772(avformat:new): codec_whitelist does not influence codec picking
by FFmpeg 02 Jan '24

02 Jan '24

#10772: codec_whitelist does not influence codec picking -------------------------------------+------------------------------------- Reporter: Rudolf | Type: defect Polzer | Status: new | Priority: important Component: avformat | Version: git- | master Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Summary of the bug: The codec_whitelist feature, as introduced in 5c8eb16769e581f828ce420373c558c190185cc1, appears to block codecs from decoding, but it does not prevent automatic codec selection from picking a blocked codec. Thus, when the feature is used and one wants to play/decode a file whose preferred codec is not on the whitelist, but a different codec is on the whitelist that can decode the file, decoding will fail unless explicitly selecting the decoder. This currently breaks Opus decoding (and thus 100% of youtube.com) in Chromium on Alpine Linux (and probably any other system that compiles Chromium to link against a system-wide installed ffmpeg library, and configures that system-wide library to contain both the opus and libopus decoders): https://gitlab.alpinelinux.org/alpine/aports/-/issues/15585 Also, as the below log shows, even when explicitly setting the codec, there still appear to be issues during analysis of the file; these do not appear to break playback though. Component set to avformat as I believe `find_probe_decoder` in `libavformat/demux.c` should take the whitelist into account and skip codecs not listed on it. Priority set to important, as Chromium being able to play YouTube videos is pretty important. Not sure if Type should really be defect or enhancement - it depends on what the intent of the codec whitelist feature was (and thus whether Chrome is abusing it). The documentation of the feature does not go into much detail. How to reproduce: (NOTE: this repro requires _any_ opus file, and a ffmpeg binary that has both the opus and libopus decoders enabled in it. For my tests I was using http://rm.cloudns.org/~xonotic/temp/b-opus.mp4) {{{ % ffplay -codec_whitelist h264,libopus /tmp/b-opus.mp4 ffplay version N-113171-g85b8d59ec7 Copyright (c) 2003-2024 the FFmpeg developers built with gcc 13 (Debian 13.2.0-5) configuration: --prefix=/home/rpolzer/src/update-ffmpeg/out --cc=gcc --cxx=g++ --objcc= --dep-cc=gcc --disable-static --enable-shared --enable- nonfree --enable-gpl --enable-version3 --enable-libaom --enable-libvpx --enable-libwebp --enable-libx264 --enable-libfribidi --enable-libass --enable-libfontconfig --enable-libfreetype --enable-libmp3lame --enable- libvorbis --enable-libopus --enable-libpulse --enable-vaapi --enable-vdpau --enable-demuxer=dash --enable-gnutls --enable-libxml2 libavutil 58. 36.100 / 58. 36.100 libavcodec 60. 36.100 / 60. 36.100 libavformat 60. 20.100 / 60. 20.100 libavdevice 60. 4.100 / 60. 4.100 libavfilter 9. 16.100 / 9. 16.100 libswscale 7. 6.100 / 7. 6.100 libswresample 4. 13.100 / 4. 13.100 libpostproc 57. 4.100 / 57. 4.100 [opus @ 0x7ff164007a80] Codec (opus) not on whitelist 'h264,libopus' [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7ff164000c80] Failed to open codec in avformat_find_stream_info [opus @ 0x7ff164007a80] Codec (opus) not on whitelist 'h264,libopus' [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7ff164000c80] Could not find codec parameters for stream 1 (Audio: opus (Opus / 0x7375704F), 48000 Hz, 0 channels, 104 kb/s): unspecified number of channels Consider increasing the value for the 'analyzeduration' (0) and 'probesize' (5000000) options Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/tmp/b-opus.mp4': Metadata: major_brand : isom minor_version : 512 compatible_brands: isomiso2avc1mp41 encoder : Lavf60.16.100 Duration: 00:00:25.48, start: 0.000000, bitrate: 884 kb/s Stream #0:0[0x1](und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt470bg/unknown/unknown, progressive), 640x360, 768 kb/s, 60 fps, 60 tbr, 15360 tbn (default) Metadata: handler_name : VideoHandler vendor_id : [0][0][0][0] encoder : Lavc60.31.102 libx264 Stream #0:1[0x2](und): Audio: opus (Opus / 0x7375704F), 48000 Hz, 2 channels, 104 kb/s (default) Metadata: handler_name : SoundHandler vendor_id : [0][0][0][0] [opus @ 0x7ff164022d80] Codec (opus) not on whitelist 'h264,libopus' Failed to open file '/tmp/b-opus.mp4' or configure filtergraph % ffplay -codec_whitelist h264,libopus -vn -codec:a libopus /tmp/b-opus.mp4 ffplay version N-113171-g85b8d59ec7 Copyright (c) 2003-2024 the FFmpeg developers built with gcc 13 (Debian 13.2.0-5) configuration: --prefix=/home/rpolzer/src/update-ffmpeg/out --cc=gcc --cxx=g++ --objcc= --dep-cc=gcc --disable-static --enable-shared --enable- nonfree --enable-gpl --enable-version3 --enable-libaom --enable-libvpx --enable-libwebp --enable-libx264 --enable-libfribidi --enable-libass --enable-libfontconfig --enable-libfreetype --enable-libmp3lame --enable- libvorbis --enable-libopus --enable-libpulse --enable-vaapi --enable-vdpau --enable-demuxer=dash --enable-gnutls --enable-libxml2 libavutil 58. 36.100 / 58. 36.100 libavcodec 60. 36.100 / 60. 36.100 libavformat 60. 20.100 / 60. 20.100 libavdevice 60. 4.100 / 60. 4.100 libavfilter 9. 16.100 / 9. 16.100 libswscale 7. 6.100 / 7. 6.100 libswresample 4. 13.100 / 4. 13.100 libpostproc 57. 4.100 / 57. 4.100 [opus @ 0x7fd82c011d40] Codec (opus) not on whitelist 'h264,libopus' [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fd82c000c80] Failed to open codec in avformat_find_stream_info [opus @ 0x7fd82c011d40] Codec (opus) not on whitelist 'h264,libopus' [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fd82c000c80] Could not find codec parameters for stream 1 (Audio: opus (Opus / 0x7375704F), 48000 Hz, 0 channels, 104 kb/s): unspecified number of channels Consider increasing the value for the 'analyzeduration' (0) and 'probesize' (5000000) options Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/tmp/b-opus.mp4': Metadata: major_brand : isom minor_version : 512 compatible_brands: isomiso2avc1mp41 encoder : Lavf60.16.100 Duration: 00:00:25.48, start: 0.000000, bitrate: 884 kb/s Stream #0:0[0x1](und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt470bg/unknown/unknown, progressive), 640x360, 768 kb/s, 60 fps, 60 tbr, 15360 tbn (default) Metadata: handler_name : VideoHandler vendor_id : [0][0][0][0] encoder : Lavc60.31.102 libx264 Stream #0:1[0x2](und): Audio: opus (Opus / 0x7375704F), 48000 Hz, 2 channels, 104 kb/s (default) Metadata: handler_name : SoundHandler vendor_id : [0][0][0][0] 0.58 M-A: 0.000 fd= 0 aq= 10KB vq= 0KB sq= 0B f=0/0 }}} -- Ticket URL: <https://trac.ffmpeg.org/ticket/10772> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker

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#10770(undetermined:new): avcodec_open2 overwrites flags contrary to what the doc says
by FFmpeg 01 Jan '24

01 Jan '24

#10770: avcodec_open2 overwrites flags contrary to what the doc says -------------------------------------+------------------------------------- Reporter: Jean- | Type: defect Michaël Celerier | Status: new | Priority: normal Component: | Version: undetermined | unspecified Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- The avcodec_open2 documentation states, about the options parameter: {{{ * @param options A dictionary filled with AVCodecContext and codec- private * options, which are set on top of the options already set in * avctx, can be NULL. On return this object will be filled with * options that were not found in the avctx codec context. }}} Yet given the following program, the final assert does not pass: AV_CODEC_FLAG_GLOBAL_HEADER gets overwritten in the codec context's flags. {{{ extern "C" { #include <libavcodec/avcodec.h> } #include <cassert> int main() { auto codec = avcodec_find_encoder_by_name("libx264"); auto c = avcodec_alloc_context3(codec); c->width = 1280; c->height = 720; c->time_base = (AVRational){100000, int(100000 * 30)}; c->framerate = AVRational{c->time_base.den, c->time_base.num}; c->gop_size = 0; c->max_b_frames = 0; c->pix_fmt = AV_PIX_FMT_YUV420P; c->strict_std_compliance = FF_COMPLIANCE_NORMAL; c->flags |= AV_CODEC_FLAG_GLOBAL_HEADER; AVDictionary* opt{}; av_dict_set(&opt, "flags", "low_delay", 0); avcodec_open2(c, codec, &opt); assert(c->flags & AV_CODEC_FLAG_GLOBAL_HEADER); } }}} -- Ticket URL: <https://trac.ffmpeg.org/ticket/10770> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker

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