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 ffmpeg version git-2020-06-19-2f59946 Copyright (c) 2000-2020 the FFmpeg developers built with gcc 9.3.1 (GCC) 20200523 configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libsrt --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --disable-w32threads --enable-libmfx --enable-ffnvcodec --enable-cuda-llvm --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt --enable-amf libavutil 56. 55.100 / 56. 55.100 libavcodec 58. 93.100 / 58. 93.100 libavformat 58. 47.100 / 58. 47.100 libavdevice 58. 11.100 / 58. 11.100 libavfilter 7. 86.100 / 7. 86.100 libswscale 5. 8.100 / 5. 8.100 libswresample 3. 8.100 / 3. 8.100 libpostproc 55. 8.100 / 55. 8.100 [h264 @ 000001967ec1ec00] non-existing PPS 0 referenced Last message repeated 1 times [h264 @ 000001967ec1ec00] decode_slice_header error [h264 @ 000001967ec1ec00] no frame! [h264 @ 000001967ec1ec00] non-existing PPS 0 referenced Last message repeated 1 times [h264 @ 000001967ec1ec00] decode_slice_header error [h264 @ 000001967ec1ec00] no frame! [mpegts @ 000001967ebfed00] start time for stream 0 is not set in estimate_timings_from_pts [mpegts @ 000001967ebfed00] start time for stream 1 is not set in estimate_timings_from_pts [mpegts @ 000001967ebfed00] Packet corrupt (stream = 0, dts = 590952620). [mpegts @ 000001967ebfed00] Packet corrupt (stream = 0, dts = 590952620). [mpegts @ 000001967ebfed00] Packet corrupt (stream = 0, dts = 590952620). [mpegts @ 000001967ebfed00] stream 0 : no TS found at start of file, duration not set [mpegts @ 000001967ebfed00] stream 1 : no TS found at start of file, duration not set Input #0, mpegts, from 'soc_udp_rx_02.ts': Duration: N/A, bitrate: N/A Program 1 Stream #0:0[0x1100]: Video: h264 (Main) ([27][0][0][0] / 0x001B), yuv420p(tv, progressive), 1280x720 [SAR 1:1 DAR 16:9], 50 fps, 50 tbr, 90k tbn, 100 tbc Stream #0:1[0x1110]: Audio: aac (LC) ([15][0][0][0] / 0x000F), 48000 Hz, stereo, fltp, 128 kb/s File 'testaudio.mp4' already exists. Overwrite? [y/N] y Output #0, mp4, to 'testaudio.mp4': Metadata: title : media source exentions encoder : Lavf58.47.100 Stream #0:0: Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, progressive), 1280x720 [SAR 1:1 DAR 16:9], q=2-31, 50 fps, 50 tbr, 90k tbn, 90k tbc Stream #0:1: Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s Stream mapping: Stream #0:0 -> #0:0 (copy) Stream #0:1 -> #0:1 (copy) Press [q] to stop, [?] for help [mpegts @ 000001967ebfed00] Packet corrupt (stream = 0, dts = 590952620). frame= 902 fps=0.0 q=-1.0 Lsize= 1803kB time=00:00:18.09 bitrate= 816.3kbits/s speed= 816x video:1469kB audio:277kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 3.293837% For although there it says aac (LC) if I run mp4info on the resultant file I get this: mp4info testaudio.mp4 File: major brand: iso5 minor version: 200 compatible brand: iso5 compatible brand: iso6 compatible brand: mp41 fast start: yes Movie: duration: 0 ms time scale: 1000 fragments: yes Found 2 Tracks Track 1: flags: 3 ENABLED IN-MOVIE id: 1 type: Video duration: 0 ms language: und media: sample count: 0 timescale: 90000 duration: 0 (media timescale units) duration: 0 (ms) bitrate (computed): 664.930 Kbps sample count with fragments: 902 duration with fragments: 1628337 duration with fragments: 18093 (ms) display width: 1280.000000 display height: 720.000000 Sample Description 0 Coding: avc1 (H.264) Width: 1280 Height: 720 Depth: 24 AVC Profile: 77 (Main) AVC Profile Compat: 0 AVC Level: 40 AVC NALU Length Size: 4 AVC SPS: [674d00288994a02802dd80b502020240000003004000001921] AVC PPS: [68ee3c8000] Codecs String: avc1.4D0028 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 whereas if I used -c:a aac -profile:a aac_low instead of -c:a copy then I get this from mp4info: 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): 49.589 Kbps sample count with fragments: 849 duration with fragments: 869378 duration with fragments: 18112 (ms) Sample Description 0 Coding: mp4a (MPEG-4 Audio) Stream Type: Audio Object Type: MPEG-4 Audio Max Bitrate: 128000 Avg Bitrate: 0 Buffer Size: 0 Codecs String: mp4a.40.2 MPEG-4 Audio Object Type: 2 (AAC Low Complexity) MPEG-4 Audio Decoder Config: Sampling Frequency: 48000 Channels: 2 Extension: Object Type: Spectral Band Replication SBR Present: no PS Present: no Sampling Frequency: 0 Sample Rate: 48000 Sample Size: 16 Channels: 2 where it clearly states it as Mpeg-4 Audio AAC Low complexity. Any help gratefully received, Thanks, Simon _______________________________________________ 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".