New submission from Andreas <[email protected]>: I use ffmpeg to transcode an MPEG transport stream from satellite tv to MP4 h.264. If I like to encode old broadcasts with mono sound (delivered in the TS) the audio is destroyed (strange noise) if the advertising break starts in the middle with stereo sound. At this point the audio is not usable anymore. ffmpeg seems to have a problem with this change during encoding. I think this is because the channel changes the stream at position 1 from mono to stereo... and this confuses ffmpeg.
Used version: FFmpeg version SVN-r25326 The command line: ffmpeg -deinterlace -threads 4 -async 50 -i - -copyts -r 25 -vcodec libx264 -b 1500k -maxrate 1650k - bufsize 1024k -s 1024x576 -flags +loop -cmp +chroma -deblockalpha 0 -deblockbeta 0 -chromaoffset -2 - refs 1 -coder 0 -me_method hex -me_range 16 -subq 6 -partitions +parti4x4+parti8x8+partp8x8 -g 250 - keyint_min 25 -level 30 -rc_eq abr -qcomp 0.60 -qmin 10 -qmax 51 -trellis 1 -sc_threshold 40 -i_qfactor 0.71 -ab 128k -ar 44100 -ac 2 -alang ger -async 0 -flags2 +wpred -f mp4 -ss 11 File.mp4 also with "-ac 1" => same problem. See sample file. File 'sample.ts' not attached - you can download it from https://roundup.ffmpeg.org/file1131. ---------- files: sample.ts messages: 12233 priority: normal status: open substatus: open title: TS encoding: audio strange noise if stream changes from mono to stereo type: bug ________________________________________________ FFmpeg issue tracker <[email protected]> <https://roundup.ffmpeg.org/issue2292> ________________________________________________
