[FFmpeg-devel] [PATCH 3/4] avformat/lc3: Add file format for LC3/LC3plus transport
A file format is described in Bluetooth SIG LC3 and ETSI TS 103 634, for test purpose. This is the format implemented here. Signed-off-by: Antoine Soulier --- doc/muxers.texi | 6 ++ libavformat/Makefile | 2 + libavformat/allformats.c | 2 + libavformat/lc3dec.c | 135 +++ libavformat/lc3enc.c | 102 + 5 files changed, 247 insertions(+) create mode 100644 libavformat/lc3dec.c create mode 100644 libavformat/lc3enc.c diff --git a/doc/muxers.texi b/doc/muxers.texi index a10a8e216f..9687746c30 100644 --- a/doc/muxers.texi +++ b/doc/muxers.texi @@ -2612,6 +2612,12 @@ WebDAV server every second: ffmpeg -f x11grab -framerate 1 -i :0.0 -q:v 6 -update 1 -protocol_opts method=PUT http://example.com/desktop.jpg @end example +@section lc3 +Bluetooth SIG Low Complexity Communication Codec audio (LC3), or +ETSI TS 103 634 Low Complexity Communication Codec plus (LC3plus). + +This muxer accepts a single @code{lc3} audio stream. + @section matroska Matroska container muxer. diff --git a/libavformat/Makefile b/libavformat/Makefile index 44aa485029..4961c42852 100644 --- a/libavformat/Makefile +++ b/libavformat/Makefile @@ -332,6 +332,8 @@ OBJS-$(CONFIG_KVAG_DEMUXER) += kvag.o OBJS-$(CONFIG_KVAG_MUXER)+= kvag.o rawenc.o OBJS-$(CONFIG_LAF_DEMUXER) += lafdec.o OBJS-$(CONFIG_LATM_MUXER)+= latmenc.o rawenc.o +OBJS-$(CONFIG_LC3_DEMUXER) += lc3dec.o +OBJS-$(CONFIG_LC3_MUXER) += lc3enc.o OBJS-$(CONFIG_LMLM4_DEMUXER) += lmlm4.o OBJS-$(CONFIG_LOAS_DEMUXER) += loasdec.o rawdec.o OBJS-$(CONFIG_LUODAT_DEMUXER)+= luodatdec.o diff --git a/libavformat/allformats.c b/libavformat/allformats.c index e15d0fa6d7..e225354faf 100644 --- a/libavformat/allformats.c +++ b/libavformat/allformats.c @@ -252,6 +252,8 @@ extern const FFInputFormat ff_kvag_demuxer; extern const FFOutputFormat ff_kvag_muxer; extern const FFInputFormat ff_laf_demuxer; extern const FFOutputFormat ff_latm_muxer; +extern const FFInputFormat ff_lc3_demuxer; +extern const FFOutputFormat ff_lc3_muxer; extern const FFInputFormat ff_lmlm4_demuxer; extern const FFInputFormat ff_loas_demuxer; extern const FFInputFormat ff_luodat_demuxer; diff --git a/libavformat/lc3dec.c b/libavformat/lc3dec.c new file mode 100644 index 00..9ca9825f1b --- /dev/null +++ b/libavformat/lc3dec.c @@ -0,0 +1,135 @@ +/* + * LC3 demuxer + * Copyright (C) 2024 Antoine Soulier + * + * This file is part of FFmpeg. + * + * FFmpeg is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * FFmpeg is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +/** + * @file + * Based on the file format specified by : + * + * - Bluetooth SIG - Low Complexity Communication Codec Test Suite + * https://www.bluetooth.org/docman/handlers/downloaddoc.ashx?doc_id=502301 + * 3.2.8.2 Reference LC3 Codec Bitstream Format + * + * - ETSI TI 103 634 V1.4.1 - Low Complexity Communication Codec plus + * https://www.etsi.org/deliver/etsi_ts/103600_103699/103634/01.04.01_60/ts_103634v010401p.pdf + * LC3plus conformance script package + */ + +#include "libavcodec/packet.h" +#include "libavutil/intreadwrite.h" + +#include "avformat.h" +#include "avio.h" +#include "demux.h" +#include "internal.h" + +typedef struct LC3DemuxContext { +int frame_samples; +int64_t position; +int64_t length; +} LC3DemuxContext; + +static int lc3_read_header(AVFormatContext *s) +{ +LC3DemuxContext *lc3 = s->priv_data; +AVStream *st = NULL; +uint16_t tag, hdr_size; +uint16_t frame_us; +uint32_t length; +int ep_mode, hr_mode; +int srate_hz, channels, bit_rate; +int num_extra_params, ret; + +tag = avio_rb16(s->pb); +hdr_size = avio_rl16(s->pb); + +if (tag != 0x1ccc || hdr_size < 9 * sizeof(uint16_t)) +return AVERROR_INVALIDDATA; + +num_extra_params = hdr_size / sizeof(uint16_t) - 9; + +srate_hz = avio_rl16(s->pb) * 100; +bit_rate = avio_rl16(s->pb) * 100; +channels = avio_rl16(s->pb); +frame_us = avio_rl16(s->pb) * 10; +ep_mode = avio_rl16(s->pb) != 0; +length = avio_rl32(s->pb); +hr_mode = num_extra_params >= 1 && avio_rl16(s->pb); + +st = avformat_new_stream(s, NULL); +if (!st) +return AVE
Re: [FFmpeg-devel] [PATCH 3/4] avformat/lc3: Add file format for LC3/LC3plus transport
This format actually supports seeking. The proposed solution here is sub-optimal. On Wed, Mar 27, 2024 at 11:22 PM Antoine Soulier via ffmpeg-devel < ffmpeg-devel@ffmpeg.org> wrote: > A file format is described in Bluetooth SIG LC3 and ETSI TS 103 634, for > test purpose. This is the format implemented here. > > Signed-off-by: Antoine Soulier > --- > doc/muxers.texi | 6 ++ > libavformat/Makefile | 2 + > libavformat/allformats.c | 2 + > libavformat/lc3dec.c | 135 +++ > libavformat/lc3enc.c | 102 + > 5 files changed, 247 insertions(+) > create mode 100644 libavformat/lc3dec.c > create mode 100644 libavformat/lc3enc.c > > diff --git a/doc/muxers.texi b/doc/muxers.texi > index a10a8e216f..9687746c30 100644 > --- a/doc/muxers.texi > +++ b/doc/muxers.texi > @@ -2612,6 +2612,12 @@ WebDAV server every second: > ffmpeg -f x11grab -framerate 1 -i :0.0 -q:v 6 -update 1 -protocol_opts > method=PUT http://example.com/desktop.jpg > @end example > > +@section lc3 > +Bluetooth SIG Low Complexity Communication Codec audio (LC3), or > +ETSI TS 103 634 Low Complexity Communication Codec plus (LC3plus). > + > +This muxer accepts a single @code{lc3} audio stream. > + > @section matroska > > Matroska container muxer. > diff --git a/libavformat/Makefile b/libavformat/Makefile > index 44aa485029..4961c42852 100644 > --- a/libavformat/Makefile > +++ b/libavformat/Makefile > @@ -332,6 +332,8 @@ OBJS-$(CONFIG_KVAG_DEMUXER) += kvag.o > OBJS-$(CONFIG_KVAG_MUXER)+= kvag.o rawenc.o > OBJS-$(CONFIG_LAF_DEMUXER) += lafdec.o > OBJS-$(CONFIG_LATM_MUXER)+= latmenc.o rawenc.o > +OBJS-$(CONFIG_LC3_DEMUXER) += lc3dec.o > +OBJS-$(CONFIG_LC3_MUXER) += lc3enc.o > OBJS-$(CONFIG_LMLM4_DEMUXER) += lmlm4.o > OBJS-$(CONFIG_LOAS_DEMUXER) += loasdec.o rawdec.o > OBJS-$(CONFIG_LUODAT_DEMUXER)+= luodatdec.o > diff --git a/libavformat/allformats.c b/libavformat/allformats.c > index e15d0fa6d7..e225354faf 100644 > --- a/libavformat/allformats.c > +++ b/libavformat/allformats.c > @@ -252,6 +252,8 @@ extern const FFInputFormat ff_kvag_demuxer; > extern const FFOutputFormat ff_kvag_muxer; > extern const FFInputFormat ff_laf_demuxer; > extern const FFOutputFormat ff_latm_muxer; > +extern const FFInputFormat ff_lc3_demuxer; > +extern const FFOutputFormat ff_lc3_muxer; > extern const FFInputFormat ff_lmlm4_demuxer; > extern const FFInputFormat ff_loas_demuxer; > extern const FFInputFormat ff_luodat_demuxer; > diff --git a/libavformat/lc3dec.c b/libavformat/lc3dec.c > new file mode 100644 > index 00..9ca9825f1b > --- /dev/null > +++ b/libavformat/lc3dec.c > @@ -0,0 +1,135 @@ > +/* > + * LC3 demuxer > + * Copyright (C) 2024 Antoine Soulier > + * > + * This file is part of FFmpeg. > + * > + * FFmpeg is free software; you can redistribute it and/or > + * modify it under the terms of the GNU Lesser General Public > + * License as published by the Free Software Foundation; either > + * version 2.1 of the License, or (at your option) any later version. > + * > + * FFmpeg is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + * Lesser General Public License for more details. > + * > + * You should have received a copy of the GNU Lesser General Public > + * License along with FFmpeg; if not, write to the Free Software > + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA > 02110-1301 USA > + */ > + > +/** > + * @file > + * Based on the file format specified by : > + * > + * - Bluetooth SIG - Low Complexity Communication Codec Test Suite > + * > https://www.bluetooth.org/docman/handlers/downloaddoc.ashx?doc_id=502301 > + * 3.2.8.2 Reference LC3 Codec Bitstream Format > + * > + * - ETSI TI 103 634 V1.4.1 - Low Complexity Communication Codec plus > + * > https://www.etsi.org/deliver/etsi_ts/103600_103699/103634/01.04.01_60/ts_103634v010401p.pdf > + * LC3plus conformance script package > + */ > + > +#include "libavcodec/packet.h" > +#include "libavutil/intreadwrite.h" > + > +#include "avformat.h" > +#include "avio.h" > +#include "demux.h" > +#include "internal.h" > + > +typedef struct LC3DemuxContext { > +int frame_samples; > +int64_t position; > +int64_t length; > +} LC3DemuxContext; > + > +static int lc3_read_header(AVFormatContext *s) > +{ > +LC3DemuxContext *lc3 = s->priv_data; > +AVStream *st = NULL; > +uint16_t tag, hdr_size; > +uint16_t frame_us; > +uint32_t length; > +int ep_mode, hr_mode; > +int srate_hz, channels, bit_rate; > +int num_extra_params, ret; > + > +tag = avio_rb16(s->pb); > +hdr_size = avio_rl16(s->pb); > + > +if (tag != 0x1ccc || hdr_size < 9 * sizeof(uint16_t)) > +return AVERROR
Re: [FFmpeg-devel] [PATCH 3/4] avformat/lc3: Add file format for LC3/LC3plus transport
I don't think it's "easy" seekable. We cannot move to an arbitrary position: - There is no start-code - The frame size can be variable (not generated by the proposed encoder implementation, but allowed). The only possibility I see is checking that the frame size looks valid for multiple frames. The range of valid frame sizes is large (20 to 625 Bytes), so I can only validate 6 bits for each 16 bits packet size read. This format is not really designed to be seekable. Do you think we will need it? On Thu, Mar 28, 2024 at 2:33 AM Paul B Mahol wrote: > This format actually supports seeking. > > The proposed solution here is sub-optimal. > > On Wed, Mar 27, 2024 at 11:22 PM Antoine Soulier via ffmpeg-devel < > ffmpeg-devel@ffmpeg.org> wrote: > >> A file format is described in Bluetooth SIG LC3 and ETSI TS 103 634, for >> test purpose. This is the format implemented here. >> >> Signed-off-by: Antoine Soulier >> --- >> doc/muxers.texi | 6 ++ >> libavformat/Makefile | 2 + >> libavformat/allformats.c | 2 + >> libavformat/lc3dec.c | 135 +++ >> libavformat/lc3enc.c | 102 + >> 5 files changed, 247 insertions(+) >> create mode 100644 libavformat/lc3dec.c >> create mode 100644 libavformat/lc3enc.c >> >> diff --git a/doc/muxers.texi b/doc/muxers.texi >> index a10a8e216f..9687746c30 100644 >> --- a/doc/muxers.texi >> +++ b/doc/muxers.texi >> @@ -2612,6 +2612,12 @@ WebDAV server every second: >> ffmpeg -f x11grab -framerate 1 -i :0.0 -q:v 6 -update 1 -protocol_opts >> method=PUT http://example.com/desktop.jpg >> @end example >> >> +@section lc3 >> +Bluetooth SIG Low Complexity Communication Codec audio (LC3), or >> +ETSI TS 103 634 Low Complexity Communication Codec plus (LC3plus). >> + >> +This muxer accepts a single @code{lc3} audio stream. >> + >> @section matroska >> >> Matroska container muxer. >> diff --git a/libavformat/Makefile b/libavformat/Makefile >> index 44aa485029..4961c42852 100644 >> --- a/libavformat/Makefile >> +++ b/libavformat/Makefile >> @@ -332,6 +332,8 @@ OBJS-$(CONFIG_KVAG_DEMUXER) += kvag.o >> OBJS-$(CONFIG_KVAG_MUXER)+= kvag.o rawenc.o >> OBJS-$(CONFIG_LAF_DEMUXER) += lafdec.o >> OBJS-$(CONFIG_LATM_MUXER)+= latmenc.o rawenc.o >> +OBJS-$(CONFIG_LC3_DEMUXER) += lc3dec.o >> +OBJS-$(CONFIG_LC3_MUXER) += lc3enc.o >> OBJS-$(CONFIG_LMLM4_DEMUXER) += lmlm4.o >> OBJS-$(CONFIG_LOAS_DEMUXER) += loasdec.o rawdec.o >> OBJS-$(CONFIG_LUODAT_DEMUXER)+= luodatdec.o >> diff --git a/libavformat/allformats.c b/libavformat/allformats.c >> index e15d0fa6d7..e225354faf 100644 >> --- a/libavformat/allformats.c >> +++ b/libavformat/allformats.c >> @@ -252,6 +252,8 @@ extern const FFInputFormat ff_kvag_demuxer; >> extern const FFOutputFormat ff_kvag_muxer; >> extern const FFInputFormat ff_laf_demuxer; >> extern const FFOutputFormat ff_latm_muxer; >> +extern const FFInputFormat ff_lc3_demuxer; >> +extern const FFOutputFormat ff_lc3_muxer; >> extern const FFInputFormat ff_lmlm4_demuxer; >> extern const FFInputFormat ff_loas_demuxer; >> extern const FFInputFormat ff_luodat_demuxer; >> diff --git a/libavformat/lc3dec.c b/libavformat/lc3dec.c >> new file mode 100644 >> index 00..9ca9825f1b >> --- /dev/null >> +++ b/libavformat/lc3dec.c >> @@ -0,0 +1,135 @@ >> +/* >> + * LC3 demuxer >> + * Copyright (C) 2024 Antoine Soulier >> + * >> + * This file is part of FFmpeg. >> + * >> + * FFmpeg is free software; you can redistribute it and/or >> + * modify it under the terms of the GNU Lesser General Public >> + * License as published by the Free Software Foundation; either >> + * version 2.1 of the License, or (at your option) any later version. >> + * >> + * FFmpeg is distributed in the hope that it will be useful, >> + * but WITHOUT ANY WARRANTY; without even the implied warranty of >> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU >> + * Lesser General Public License for more details. >> + * >> + * You should have received a copy of the GNU Lesser General Public >> + * License along with FFmpeg; if not, write to the Free Software >> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA >> 02110-1301 USA >> + */ >> + >> +/** >> + * @file >> + * Based on the file format specified by : >> + * >> + * - Bluetooth SIG - Low Complexity Communication Codec Test Suite >> + * >> https://www.bluetooth.org/docman/handlers/downloaddoc.ashx?doc_id=502301 >> + * 3.2.8.2 Reference LC3 Codec Bitstream Format >> + * >> + * - ETSI TI 103 634 V1.4.1 - Low Complexity Communication Codec plus >> + * >> https://www.etsi.org/deliver/etsi_ts/103600_103699/103634/01.04.01_60/ts_103634v010401p.pdf >> + * LC3plus conformance script package >> + */ >> + >> +#include "libavcodec/packet.h" >> +#include "libavutil/intreadwrite.h" >> + >> +#include "avformat.h" >> +#i
Re: [FFmpeg-devel] [PATCH 3/4] avformat/lc3: Add file format for LC3/LC3plus transport
On date Wednesday 2024-03-27 22:21:44 +, ffmpeg-devel Mailing List wrote: > A file format is described in Bluetooth SIG LC3 and ETSI TS 103 634, for > test purpose. This is the format implemented here. > > Signed-off-by: Antoine Soulier > --- > doc/muxers.texi | 6 ++ > libavformat/Makefile | 2 + > libavformat/allformats.c | 2 + > libavformat/lc3dec.c | 135 +++ > libavformat/lc3enc.c | 102 + > 5 files changed, 247 insertions(+) > create mode 100644 libavformat/lc3dec.c > create mode 100644 libavformat/lc3enc.c Note: you might add an entry for muxing/demuxing support to the Changelog. Looks good to me otherwise. ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH 3/4] avformat/lc3: Add file format for LC3/LC3plus transport
On Thu, Mar 28, 2024 at 5:40 PM Antoine Soulier wrote: > I don't think it's "easy" seekable. > We cannot move to an arbitrary position: > - There is no start-code > Not relevant. > - The frame size can be variable (not generated by the proposed encoder > implementation, but allowed). > Not relevant. > > The only possibility I see is checking that the frame size looks valid for > multiple frames. > Not relevant, the only needed feature is known stored number of samples in each packet for proper pts/timestamp generation. The range of valid frame sizes is large (20 to 625 Bytes), so I can only > validate 6 bits for each 16 bits packet size read. > > This format is not really designed to be seekable. > Do you think we will need it? > I cant force you do to correct implementation. Seeking is possible, just you are not aware of actual solution. Hint: see other demuxers. > > > On Thu, Mar 28, 2024 at 2:33 AM Paul B Mahol wrote: > >> This format actually supports seeking. >> >> The proposed solution here is sub-optimal. >> >> On Wed, Mar 27, 2024 at 11:22 PM Antoine Soulier via ffmpeg-devel < >> ffmpeg-devel@ffmpeg.org> wrote: >> >>> A file format is described in Bluetooth SIG LC3 and ETSI TS 103 634, for >>> test purpose. This is the format implemented here. >>> >>> Signed-off-by: Antoine Soulier >>> --- >>> doc/muxers.texi | 6 ++ >>> libavformat/Makefile | 2 + >>> libavformat/allformats.c | 2 + >>> libavformat/lc3dec.c | 135 +++ >>> libavformat/lc3enc.c | 102 + >>> 5 files changed, 247 insertions(+) >>> create mode 100644 libavformat/lc3dec.c >>> create mode 100644 libavformat/lc3enc.c >>> >>> diff --git a/doc/muxers.texi b/doc/muxers.texi >>> index a10a8e216f..9687746c30 100644 >>> --- a/doc/muxers.texi >>> +++ b/doc/muxers.texi >>> @@ -2612,6 +2612,12 @@ WebDAV server every second: >>> ffmpeg -f x11grab -framerate 1 -i :0.0 -q:v 6 -update 1 -protocol_opts >>> method=PUT http://example.com/desktop.jpg >>> @end example >>> >>> +@section lc3 >>> +Bluetooth SIG Low Complexity Communication Codec audio (LC3), or >>> +ETSI TS 103 634 Low Complexity Communication Codec plus (LC3plus). >>> + >>> +This muxer accepts a single @code{lc3} audio stream. >>> + >>> @section matroska >>> >>> Matroska container muxer. >>> diff --git a/libavformat/Makefile b/libavformat/Makefile >>> index 44aa485029..4961c42852 100644 >>> --- a/libavformat/Makefile >>> +++ b/libavformat/Makefile >>> @@ -332,6 +332,8 @@ OBJS-$(CONFIG_KVAG_DEMUXER) += kvag.o >>> OBJS-$(CONFIG_KVAG_MUXER)+= kvag.o rawenc.o >>> OBJS-$(CONFIG_LAF_DEMUXER) += lafdec.o >>> OBJS-$(CONFIG_LATM_MUXER)+= latmenc.o rawenc.o >>> +OBJS-$(CONFIG_LC3_DEMUXER) += lc3dec.o >>> +OBJS-$(CONFIG_LC3_MUXER) += lc3enc.o >>> OBJS-$(CONFIG_LMLM4_DEMUXER) += lmlm4.o >>> OBJS-$(CONFIG_LOAS_DEMUXER) += loasdec.o rawdec.o >>> OBJS-$(CONFIG_LUODAT_DEMUXER)+= luodatdec.o >>> diff --git a/libavformat/allformats.c b/libavformat/allformats.c >>> index e15d0fa6d7..e225354faf 100644 >>> --- a/libavformat/allformats.c >>> +++ b/libavformat/allformats.c >>> @@ -252,6 +252,8 @@ extern const FFInputFormat ff_kvag_demuxer; >>> extern const FFOutputFormat ff_kvag_muxer; >>> extern const FFInputFormat ff_laf_demuxer; >>> extern const FFOutputFormat ff_latm_muxer; >>> +extern const FFInputFormat ff_lc3_demuxer; >>> +extern const FFOutputFormat ff_lc3_muxer; >>> extern const FFInputFormat ff_lmlm4_demuxer; >>> extern const FFInputFormat ff_loas_demuxer; >>> extern const FFInputFormat ff_luodat_demuxer; >>> diff --git a/libavformat/lc3dec.c b/libavformat/lc3dec.c >>> new file mode 100644 >>> index 00..9ca9825f1b >>> --- /dev/null >>> +++ b/libavformat/lc3dec.c >>> @@ -0,0 +1,135 @@ >>> +/* >>> + * LC3 demuxer >>> + * Copyright (C) 2024 Antoine Soulier >>> + * >>> + * This file is part of FFmpeg. >>> + * >>> + * FFmpeg is free software; you can redistribute it and/or >>> + * modify it under the terms of the GNU Lesser General Public >>> + * License as published by the Free Software Foundation; either >>> + * version 2.1 of the License, or (at your option) any later version. >>> + * >>> + * FFmpeg is distributed in the hope that it will be useful, >>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of >>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU >>> + * Lesser General Public License for more details. >>> + * >>> + * You should have received a copy of the GNU Lesser General Public >>> + * License along with FFmpeg; if not, write to the Free Software >>> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA >>> 02110-1301 USA >>> + */ >>> + >>> +/** >>> + * @file >>> + * Based on the file format specified by : >>> + * >>> + * - Bluetooth SIG - Low Complexity Communication Codec Test Suit
Re: [FFmpeg-devel] [PATCH 3/4] avformat/lc3: Add file format for LC3/LC3plus transport
You're right, I was not aware at all. I have pushed a patch that does the job. PTAL, thanks. ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".