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 libavformat 55. 33.100 / 55. 33.100 libavdevice 55. 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 libpostproc 52. 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 0.000000% 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 libavformat 55. 33.100 / 55. 33.100 libavdevice 55. 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 libpostproc 52. 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 0.000000% 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