On Fri, May 14, 2021 at 14:31:42 +0100, Simon Brown wrote: > Hi, > I have a mpeg2 transport stream with video as H264 and audio as AAC LC. If > I use the following command to convert it to fragmented MP4 by just copying > the encoded data, then the result is now AAC, and not AAC LC. If instead I > re-encode with AAC asking for profile:a aac_low then I get AAC LC. But if > the input source is AAC LC why would it change the output type to AAC? > > ffmpeg.exe -f mpegts -fflags +nobuffer+nofillin -probesize 5000000 -i > soc_udp_rx_02.ts -c:a copy -bsf:a aac_adtstoasc -c:v copy -f mp4 > -frag_duration 80000 -movflags +empty_moov+default_base_moof -metadata > title="media source exentions" testaudio.mp4
This shouldn't change anything in the AAC stream, unless the bitstream filter is capable of ruining it. > ffmpeg version git-2020-06-19-2f59946 Copyright (c) 2000-2020 the FFmpeg > developers This is a bit old, please retry with a recent build. > For although there it says aac (LC) if I run mp4info on the resultant file > I get this: > > mp4info testaudio.mp4 [...] > Track 2: > flags: 3 ENABLED IN-MOVIE > id: 2 > type: Audio > duration: 0 ms > language: und > media: > sample count: 0 > timescale: 48000 > duration: 0 (media timescale units) > duration: 0 (ms) > bitrate (computed): 125.373 Kbps > sample count with fragments: 848 > duration with fragments: 868354 > duration with fragments: 18091 (ms) > Sample Description 0 > Coding: mp4a (MPEG-4 Audio) > Stream Type: Audio > Object Type: MPEG-4 Audio > Max Bitrate: 128250 > Avg Bitrate: 0 > Buffer Size: 0 > Codecs String: mp4a.40.0 > MPEG-4 Audio Object Type: 0 (UNKNOWN) > Sample Rate: 48000 > Sample Size: 16 > Channels: 2 What does it say about the original? (Nothing, presumably, because it's MPEG-TS.) What does ffmpeg say about the output file? Do you have any other tool which can use to check? Cheers, Moritz _______________________________________________ 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".
