Re: [FFmpeg-user] HEVC decoding
On Tue, 3 Mar 2020 at 21:43, Mohammed Bey Ahmed Khernache
wrote:
>
> Hello,
> which API or plug-in does ffmpeg use to decode HEVC-coded content?
> Is HEVC-Tiles-based parallelism supported by ffmpeg?
>
> Best regards
Hello Ahmed,
There's a native (software-based) HEVC decoder in FFmpeg with the
following capabilities:
ffmpeg -h decoder=hevc
Decoder hevc [HEVC (High Efficiency Video Coding)]:
General capabilities: dr1 delay threads
Threading capabilities: frame and slice
Supported hardware devices: cuda vdpau
HEVC decoder AVOptions:
-apply_defdispwin .D.V.. Apply default display
window from VUI (default false)
-strict-displaywin .D.V.. stricly apply default
display window size (default false)
This is the decoder that ffmpeg will fall back on *if* no hwaccel is
specified on launch.
The capabilities for the same are as listed above, including threading
capabilities.
Depending on how your ffmpeg build is configured, there *may* be extra
decode wrappers present, which you can list via:
ffmpeg -decoders | grep hevc
Which, on my machine, returns:
VFS..D hevc HEVC (High Efficiency Video Coding)
V. hevc_v4l2m2m V4L2 mem2mem HEVC decoder wrapper (codec hevc)
V. hevc_cuvid Nvidia CUVID HEVC decoder (codec hevc)
Private options for the same can be viewed via:
ffmpeg -h decoder={wrapper_name}
Where available.
Your mileage will vary based on how your build was configured and the
environment you're on.
Warm regards,
Dennis.
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Re: [FFmpeg-user] HEVC decoding
FFMPEG is written in C and I believe it doesn’t use plug-ins or APIs to decode HEVC. Paul > On Mar 3, 2020, at 1:43 PM, Mohammed Bey Ahmed Khernache > wrote: > Hello, which API or plug-in does ffmpeg use to decode HEVC-coded content? Is HEVC-Tiles-based parallelism supported by ffmpeg? Best regards ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe". ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
[FFmpeg-user] HEVC decoding
Hello, which API or plug-in does ffmpeg use to decode HEVC-coded content? Is HEVC-Tiles-based parallelism supported by ffmpeg? Best regards ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-user] HEVC decoding of first frame
On Fri, Oct 16, 2015 at 12:23:14 +0200, Christian Herglotz wrote: > Hello, > > a) I know that there is some overhead. So I also tested this for > sequences with different resolutions where I could observe the same > behavior: Okay, point taken. There's a new thread on ffmpeg-devel which points out that certain formats decode the first image twice (once for format detection, once for actual decoding). The described behavior may be identical to yours: http://ffmpeg.org/pipermail/ffmpeg-devel/2015-October/181529.html Moritz ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user
Re: [FFmpeg-user] HEVC decoding of first frame
Christian Herglotz fau.de> writes: > Mean decoding times for FFmpegHM > 460*240 1 I-frame: 0.15s0.18s > 460*240 2 I-frames:0.23s0.36s I may absolutely misunderstand what you are trying to show but please understand that afaik, the two decoders cannot be compared. Please provide command line and complete, uncut console output, add -threads 1 if you really want to measure performance decoding one frame and please test current FFmpeg git head, nothing else is supported on this mailing list. Please don't top-post here, Carl Eugen ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user
Re: [FFmpeg-user] HEVC decoding of first frame
Hello, a) I know that there is some overhead. So I also tested this for sequences with different resolutions where I could observe the same behavior: Mean decoding times for FFmpegHM 460*240 1 I-frame: 0.15s0.18s 460*240 2 I-frames:0.23s0.36s 1920*1080 1 I-frame: 2.26s2.89s 1920*1080 2 I-frames: 3.43s5.8s 2560*1600 1 I-frame: 4.25s5.46s 2560*1600 2 I-frames: 6.43s11s A constant offset would not scale like this. Furthermore, I'm giving the corresponding decoding times for the HM-software as a reference where obviously the decoding time doubles for all cases. b) The bit streams I am talking about are all-intra coded. Thanks for your help! Grüße zurück aus Franken! Christian Am 16.10.2015 um 11:37 schrieb Moritz Barsnick: On Thu, Oct 15, 2015 at 08:22:35 +0200, Christian Herglotz wrote: When timing the process I found that the decoding of the first frame always takes twice as long as the decoding of all the other frames. I'm not sure I consider the test you provide as valid. a) Initializing a decoder has (some) overhead. That aligns your numbers a bit more. b) HEVC does not only consist of I-frames (unless you claim the opposite of your content). Who says P- or B-frames are easier/faster to decode than I-frames? That's just the theory from me. Someone who knows the code could help more, or someone who is willing to add the benchmarking macros into the code and rebuild. :-) Cheers, Gruß nach Franken, Moritz ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user -- Dipl.-Ing. Dipl.-Wirt.Ing. Christian Herglotz Chair of Multimedia Communications and Signal Processing Friedrich-Alexander University Erlangen-Nürnberg Cauerstr. 7, D-91058 Erlangen, Germany ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user
Re: [FFmpeg-user] HEVC decoding of first frame
On Thu, Oct 15, 2015 at 08:22:35 +0200, Christian Herglotz wrote: > When timing the process I found that the decoding of the > first frame always takes twice as long as the decoding of all the other > frames. I'm not sure I consider the test you provide as valid. a) Initializing a decoder has (some) overhead. That aligns your numbers a bit more. b) HEVC does not only consist of I-frames (unless you claim the opposite of your content). Who says P- or B-frames are easier/faster to decode than I-frames? That's just the theory from me. Someone who knows the code could help more, or someone who is willing to add the benchmarking macros into the code and rebuild. :-) Cheers, Gruß nach Franken, Moritz ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user
Re: [FFmpeg-user] HEVC decoding of first frame
Hello, thanks for the quick answer! I upgraded my ffmpeg to version 2.8 and still observe the same problem as stated before: When timing the process I found that the decoding of the first frame always takes twice as long as the decoding of all the other frames. Output of stream 1: root@herglotz-panda:/ramcache# time -p taskset -c 0 ./ffmpeg -i PeopleOnStreet_intra_1frames_QP10.bin -f rawvideo -y /dev/null ffmpeg version 2.8 Copyright (c) 2000-2015 the FFmpeg developers built with gcc 4.6 (Ubuntu/Linaro 4.6.3-1ubuntu5) configuration: libavutil 54. 31.100 / 54. 31.100 libavcodec 56. 60.100 / 56. 60.100 libavformat56. 40.101 / 56. 40.101 libavdevice56. 4.100 / 56. 4.100 libavfilter 5. 40.101 / 5. 40.101 libswscale 3. 1.101 / 3. 1.101 libswresample 1. 2.101 / 1. 2.101 Input #0, hevc, from 'PeopleOnStreet_intra_1frames_QP10.bin': Duration: N/A, bitrate: N/A Stream #0:0: Video: hevc (Main), yuv420p(tv), 2560x1600, 25 tbr, 1200k tbn, 25 tbc Output #0, rawvideo, to '/dev/null': Metadata: encoder : Lavf56.40.101 Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 2560x1600, q=2-31, 200 kb/s, 25 fps, 25 tbn, 25 tbc Metadata: encoder : Lavc56.60.100 rawvideo Stream mapping: Stream #0:0 -> #0:0 (hevc (native) -> rawvideo (native)) Press [q] to stop, [?] for help frame=1 fps=0.5 q=-0.0 size=6000kB time=00:00:00.04 bitrate=1228800.0kbiframe=1 fps=0.5 q=-0.0 Lsize=6000kB time=00:00:00.04 bitrate=1228800.0kbits/s video:6000kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.00% real 4.39 user 4.28 sys 0.10 Output of stream 2: root@herglotz-panda:/ramcache# time -p taskset -c 0 ./ffmpeg -i PeopleOnStreet_intra_2frames_QP10.bin -f rawvideo -y /dev/null ffmpeg version 2.8 Copyright (c) 2000-2015 the FFmpeg developers built with gcc 4.6 (Ubuntu/Linaro 4.6.3-1ubuntu5) configuration: libavutil 54. 31.100 / 54. 31.100 libavcodec 56. 60.100 / 56. 60.100 libavformat56. 40.101 / 56. 40.101 libavdevice56. 4.100 / 56. 4.100 libavfilter 5. 40.101 / 5. 40.101 libswscale 3. 1.101 / 3. 1.101 libswresample 1. 2.101 / 1. 2.101 Input #0, hevc, from 'PeopleOnStreet_intra_2frames_QP10.bin': Duration: N/A, bitrate: N/A Stream #0:0: Video: hevc (Main), yuv420p(tv), 2560x1600, 25 tbr, 1200k tbn, 25 tbc Output #0, rawvideo, to '/dev/null': Metadata: encoder : Lavf56.40.101 Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 2560x1600, q=2-31, 200 kb/s, 25 fps, 25 tbn, 25 tbc Metadata: encoder : Lavc56.60.100 rawvideo Stream mapping: Stream #0:0 -> #0:0 (hevc (native) -> rawvideo (native)) Press [q] to stop, [?] for help frame=2 fps=0.9 q=-0.0 size= 12000kB time=00:00:00.08 bitrate=1228800.0kbiframe=2 fps=0.5 q=-0.0 size= 12000kB time=00:00:00.08 bitrate=1228800.0kbiframe=2 fps=0.5 q=-0.0 Lsize= 12000kB time=00:00:00.08 bitrate=1228800.0kbits/s video:12000kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.00% real 6.62 user 6.40 sys 0.21 This observation is also holds for sequences with a lower resolution. Thanks for your help! Christian Am 18.09.2015 um 09:39 schrieb Moritz Barsnick: Hallo Christian, On Thu, Sep 17, 2015 at 10:48:16 +0200, Christian Herglotz wrote: I've got a question regarding the decoding process for HEVC-coded sequences. When timing the process I found that the decoding of the first frame always takes twice as long as the decoding of all the other frames. While I'm happy to try to reproduce your problem and ask smart questions, let me please point out: ffmpeg version 2.1.git Copyright (c) 2000-2014 the FFmpeg developers built on Feb 20 2014 16:27:13 with gcc 4.6 (Ubuntu/Linaro 4.6.3-1ubuntu5) This version of ffmpeg is extremely old, considering the amount of development happening. Especially with such a "new" codec as HEVC, you can expect many improvements over 18 months. And if ffmpeg happens/happened to have a bug, it may very well have been fixed in the meantime. Nobody here will help trying to identify a bug in such an old version. Please repeat your tests with a very recent version of ffmpeg, best is if you build if from git HEAD. Thanks, Gruß, Moritz ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user -- Dipl.-Ing. Dipl.-Wirt.Ing. Christian Herglotz Chair of Multimedia Communications and Signal Processing Friedrich-Alexander University Erlangen-Nürnberg Cauerstr. 7, D-91058 Erlangen, Germany ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user
Re: [FFmpeg-user] HEVC decoding of first frame
Hallo Christian, On Thu, Sep 17, 2015 at 10:48:16 +0200, Christian Herglotz wrote: > I've got a question regarding the decoding process for HEVC-coded > sequences. When timing the process I found that the decoding of the > first frame always takes twice as long as the decoding of all the other > frames. While I'm happy to try to reproduce your problem and ask smart questions, let me please point out: > ffmpeg version 2.1.git Copyright (c) 2000-2014 the FFmpeg developers >built on Feb 20 2014 16:27:13 with gcc 4.6 (Ubuntu/Linaro 4.6.3-1ubuntu5) This version of ffmpeg is extremely old, considering the amount of development happening. Especially with such a "new" codec as HEVC, you can expect many improvements over 18 months. And if ffmpeg happens/happened to have a bug, it may very well have been fixed in the meantime. Nobody here will help trying to identify a bug in such an old version. Please repeat your tests with a very recent version of ffmpeg, best is if you build if from git HEAD. Thanks, Gruß, Moritz ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user
[FFmpeg-user] HEVC decoding of first frame
Hello everyone, I've got a question regarding the decoding process for HEVC-coded sequences. When timing the process I found that the decoding of the first frame always takes twice as long as the decoding of all the other frames. This seems to be true independent from the resolution. It is also not related to inter coding, as all frames are intra coded with the same QP in the example given below. Other decoders (e.g. HM or libde265) do not show this behavior for the same input sequences. Here is an examplary output for a single frame and for two frames. It is timed using the linux time-function, furthermore single core processing is forced and priority is set to the highest level. System: Ubuntu 12.04, Pandaboard with OMAP4430 SoC Command line for single frame: time -p taskset -c 0 nice -n-30 /root/bin/ffmpeg -i PeopleOnStreet_intra_1frames_QP10.bin -f rawvideo -y /dev/null Output: ffmpeg version 2.1.git Copyright (c) 2000-2014 the FFmpeg developers built on Feb 20 2014 16:27:13 with gcc 4.6 (Ubuntu/Linaro 4.6.3-1ubuntu5) configuration: --prefix=/root/ffmpeg_build --extra-cflags=-I/root/ffmpeg_build/include --extra-ldflags=-L/root/ffmpeg_build/lib --bindir=/root/bin --extra-libs=-ldl --enable-gpl --enable-libass --enable-nonfree libavutil 52. 64.100 / 52. 64.100 libavcodec 55. 52.102 / 55. 52.102 libavformat55. 33.100 / 55. 33.100 libavdevice55. 10.100 / 55. 10.100 libavfilter 4. 1.103 / 4. 1.103 libswscale 2. 5.101 / 2. 5.101 libswresample 0. 17.104 / 0. 17.104 libpostproc52. 3.100 / 52. 3.100 Input #0, hevc, from 'PeopleOnStreet_intra_1frames_QP10.bin': Duration: N/A, bitrate: N/A Stream #0:0: Video: hevc (Main), yuv420p(tv), 2560x1600, 25 tbr, 1200k tbn, 25 tbc Output #0, rawvideo, to '/dev/null': Metadata: encoder : Lavf55.33.100 Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 2560x1600, q=2-31, 200 kb/s, 90k tbn, 25 tbc Stream mapping: Stream #0:0 -> #0:0 (hevc -> rawvideo) Press [q] to stop, [?] for help frame=1 fps=0.3 q=0.0 size=6000kB time=00:00:00.04 bitrate=1228800.0kbitframe=1 fps=0.3 q=0.0 Lsize=6000kB time=00:00:00.04 bitrate=1228800.0kbits/s video:6000kB audio:0kB subtitle:0 data:0 global headers:0kB muxing overhead 0.00% real 5.93 user 5.69 sys 0.22 Command line two frames: time -p taskset -c 0 nice -n-30 /root/bin/ffmpeg -i PeopleOnStreet_intra_2frames_QP10.bin -f rawvideo -y /dev/null Output: ffmpeg version 2.1.git Copyright (c) 2000-2014 the FFmpeg developers built on Feb 20 2014 16:27:13 with gcc 4.6 (Ubuntu/Linaro 4.6.3-1ubuntu5) configuration: --prefix=/root/ffmpeg_build --extra-cflags=-I/root/ffmpeg_build/include --extra-ldflags=-L/root/ffmpeg_build/lib --bindir=/root/bin --extra-libs=-ldl --enable-gpl --enable-libass --enable-nonfree libavutil 52. 64.100 / 52. 64.100 libavcodec 55. 52.102 / 55. 52.102 libavformat55. 33.100 / 55. 33.100 libavdevice55. 10.100 / 55. 10.100 libavfilter 4. 1.103 / 4. 1.103 libswscale 2. 5.101 / 2. 5.101 libswresample 0. 17.104 / 0. 17.104 libpostproc52. 3.100 / 52. 3.100 Input #0, hevc, from 'PeopleOnStreet_intra_2frames_QP10.bin': Duration: N/A, bitrate: N/A Stream #0:0: Video: hevc (Main), yuv420p(tv), 2560x1600, 25 tbr, 1200k tbn, 25 tbc Output #0, rawvideo, to '/dev/null': Metadata: encoder : Lavf55.33.100 Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 2560x1600, q=2-31, 200 kb/s, 90k tbn, 25 tbc Stream mapping: Stream #0:0 -> #0:0 (hevc -> rawvideo) Press [q] to stop, [?] for help frame=2 fps=0.7 q=0.0 size= 12000kB time=00:00:00.08 bitrate=1228800.0kbitframe=2 fps=0.3 q=0.0 size= 12000kB time=00:00:00.08 bitrate=1228800.0kbitframe=2 fps=0.3 q=0.0 Lsize= 12000kB time=00:00:00.08 bitrate=1228800.0kbits/s video:12000kB audio:0kB subtitle:0 data:0 global headers:0kB muxing overhead 0.00% real 8.88 user 8.58 sys 0.28 Apparently, decoding of a single frame takes about 6s, decoding of two frames about 9s. Is it possible that the first frame is always decoded twice in this software? Thanks for your help! Christian Herglotz -- Dipl.-Ing. Dipl.-Wirt.Ing. Christian Herglotz Chair of Multimedia Communications and Signal Processing Friedrich-Alexander University Erlangen-Nürnberg Cauerstr. 7, D-91058 Erlangen, Germany ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user
