#3455(ffmpeg:new): aresample=matrix_encoding=dplii doesn't downmix backleft and center correctly
#3455: aresample=matrix_encoding=dplii doesn't downmix backleft and center correctly -------------------------------------+------------------------------------- Reporter: Peter | Type: defect Status: new | Priority: normal Component: ffmpeg | Version: git- Keywords: aresample | master matrix_encoding dplii | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Summary of the bug: DPLII files have too-loud right channel. Seems to be some problem with the interaction of back left and center channel How to reproduce: {{{ ffmpeg -i surround_blbrc.wav -af "aresample=matrix_encoding=dplii" -ac 2 dplii_blbrc.wav ffmpeg version git-2014-03-09-8dfd0e6 built on Mar 9 2014 22:53:26 with gcc 4.8.2 (Gentoo 4.8.2 p1.3r1, pie-0.5.8r1) }}} You can see the problem easiest by crafting a 5.1 surround wave file with empty channels except the center channel with noise and the two back channels, first half of the back left with noise and the second half of the back right with noise. However, all surround files that use the bl and center channels at the same time will be too loud in the resulting file's right channel. Can provide example files if you like. -- Ticket URL: <https://trac.ffmpeg.org/ticket/3455> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
#3455: aresample=matrix_encoding=dplii doesn't downmix backleft and center correctly ------------------------------------+-------------------------------------- Reporter: Peter | Owner: Type: defect | Status: new Priority: normal | Component: swresample Version: git-master | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | ------------------------------------+-------------------------------------- Changes (by cehoyos): * keywords: aresample matrix_encoding dplii => * component: ffmpeg => swresample Comment: Please provide your failing command line together with the complete, uncut console output and please provide a sample. -- Ticket URL: <https://trac.ffmpeg.org/ticket/3455#comment:1> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
#3455: aresample=matrix_encoding=dplii doesn't downmix backleft and center correctly ------------------------------------+-------------------------------------- Reporter: Peter | Owner: Type: defect | Status: new Priority: normal | Component: swresample Version: git-master | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | ------------------------------------+-------------------------------------- Comment (by Peter): peter@Chip /run/media/peter/FRAPs/LetsPlay $ ~/mplayer/ffmpeg/ffmpeg -i surround_blbrc.wav -af "aresample=matrix_encoding=dplii" -ac 2 dplii_blbrc.wav ffmpeg version git-2014-03-09-8dfd0e6 Copyright (c) 2000-2014 the FFmpeg developers built on Mar 9 2014 22:53:26 with gcc 4.8.2 (Gentoo 4.8.2 p1.3r1, pie-0.5.8r1) configuration: --enable-libx264 --enable-gpl libavutil 52. 66.101 / 52. 66.101 libavcodec 55. 52.102 / 55. 52.102 libavformat 55. 34.100 / 55. 34.100 libavdevice 55. 11.100 / 55. 11.100 libavfilter 4. 3.100 / 4. 3.100 libswscale 2. 5.101 / 2. 5.101 libswresample 0. 18.100 / 0. 18.100 libpostproc 52. 3.100 / 52. 3.100 Guessed Channel Layout for Input Stream #0.0 : 5.1 Input #0, wav, from 'surround_blbrc.wav': Duration: 00:00:01.01, bitrate: 4608 kb/s Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 48000 Hz, 5.1, s16, 4608 kb/s File 'dplii_blbrc.wav' already exists. Overwrite ? [y/N] y Output #0, wav, to 'dplii_blbrc.wav': Metadata: ISFT : Lavf55.34.100 Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 48000 Hz, stereo, s16, 1536 kb/s Stream mapping: Stream #0:0 -> #0:0 (pcm_s16le -> pcm_s16le) Press [q] to stop, [?] for help size= 189kB time=00:00:01.01 bitrate=1536.6kbits/s video:0kB audio:189kB subtitle:0 data:0 global headers:0kB muxing overhead 0.041252% -- Ticket URL: <https://trac.ffmpeg.org/ticket/3455#comment:2> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
#3455: aresample=matrix_encoding=dplii doesn't downmix backleft and center correctly ------------------------------------+-------------------------------------- Reporter: Peter | Owner: Type: defect | Status: new Priority: normal | Component: swresample Version: git-master | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | ------------------------------------+-------------------------------------- Comment (by Peter): I can fix this problem by inverting the back-left channel of my source files before letting ffmpeg do its thing - it seems like ffmpeg is subtracting the back left from the center channel rather than adding it which means it is inverting the back-left when it shouldn't or not inverting it when it should. I'll do some tinkering over the weekend and see if I can't figure out some demonstration to attach. -- Ticket URL: <https://trac.ffmpeg.org/ticket/3455#comment:3> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
#3455: aresample=matrix_encoding=dplii doesn't downmix backleft and center correctly ------------------------------------+-------------------------------------- Reporter: Peter | Owner: Type: defect | Status: new Priority: normal | Component: swresample Version: git-master | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | ------------------------------------+-------------------------------------- Comment (by cehoyos): The sample you uploaded is to short to do any test imo, I tested with a file that you should be able to find with Google: {{{ $ ffmpeg -i Test\ AC3\ v2.0.avi -af "aresample=matrix_encoding=dplii" -ac 2 out.wav $ ffmpeg -i Test\ AC3\ v2.0.avi -af "aresample=matrix_encoding=dplii" -ac 2 out.ac3 $ ffmpeg -i Test\ AC3\ v2.0.avi -af "aresample=matrix_encoding=dplii" -ac 2 out.eac3 }}} I now set my receiver to "PLII" and played the three files over the digital connection (HDMI): The surround sound sounded as expected (surround sound although I used stereo files). I finally tested the wav file over the analog connection and the stereo signal also played like a surround signal. Or do I misunderstand the problem? -- Ticket URL: <https://trac.ffmpeg.org/ticket/3455#comment:4> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
#3455: aresample=matrix_encoding=dplii doesn't downmix backleft and center correctly ------------------------------------+-------------------------------------- Reporter: Peter | Owner: Type: defect | Status: new Priority: normal | Component: swresample Version: git-master | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | ------------------------------------+-------------------------------------- Comment (by cehoyos): The suggested patch can be found here: http://thread.gmane.org/gmane.comp.video.ffmpeg.devel/175700 http://ffmpeg.org/pipermail/ffmpeg-devel/2014-March/155559.html -- Ticket URL: <https://trac.ffmpeg.org/ticket/3455#comment:5> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
#3455: aresample=matrix_encoding=dplii doesn't downmix backleft and center correctly ------------------------------------+-------------------------------------- Reporter: Peter | Owner: Type: defect | Status: new Priority: normal | Component: swresample Version: git-master | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | ------------------------------------+-------------------------------------- Comment (by cehoyos): See also #4175. -- Ticket URL: <https://trac.ffmpeg.org/ticket/3455#comment:6> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
#3455: aresample=matrix_encoding=dplii doesn't downmix backleft and center correctly ------------------------------------+-------------------------------------- Reporter: Peter | Owner: Type: defect | Status: new Priority: normal | Component: swresample Version: git-master | Resolution: Keywords: dplii | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | ------------------------------------+-------------------------------------- Changes (by cehoyos): * keywords: => dplii -- Ticket URL: <https://trac.ffmpeg.org/ticket/3455#comment:7> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
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