Problems with AAC and qtdemux
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Im trying to play MP4 files with my AAC Decoder but im having problems.
the file im playing is 'cooper.mp4' from these samples http://www.mp3-tech.org/tests/aac_48/samples/sample6.zip this is a 48Khz LC-AAC with SBR (ie HE-AAC), looking a this with qtdemux and fakesink gives: gst-launch -vvv filesrc location=cooper.mp4 ! qtdemux ! fakesink | more .... caps = audio/mpeg, mpegversion=(int)4, framed=(boolean)true, stream-format=(string)raw, codec_data=(buffer)139056e5a0, rate=(int)44100, channels=(int)2 .... So as qtdemux gives us raw data (not adts or adif framed) I need to setup my decoder on the info provided by qtdemux, unfortunatley it gives me the wrong sample rate 44.1 instead of 48 and I need to know that the profile has SBR as this effects my decoder setup. How do other AAC decoders deal with this? Do they just parse the raw data, I cant easily do this as my plugin is for a hardware decoder. Any help appreciated, Cheers, Neil _______________________________________________ gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
Re: Problems with AAC and qtdemux
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On Monday, March 19, 2012, Neil Jones wrote:
> Im trying to play MP4 files with my AAC Decoder but im having problems. > > the file im playing is 'cooper.mp4' from these samples > http://www.mp3-tech.org/tests/aac_48/samples/sample6.zip > > this is a 48Khz LC-AAC with SBR (ie HE-AAC), looking a this with > qtdemux and fakesink gives: > > > gst-launch -vvv filesrc location=cooper.mp4 ! qtdemux ! fakesink | more > > .... > caps = audio/mpeg, mpegversion=(int)4, framed=(boolean)true, > stream-format=(string)raw, codec_data=(buffer)139056e5a0, > rate=(int)44100, channels=(int)2 > .... > > So as qtdemux gives us raw data (not adts or adif framed) I need to > setup my decoder on the info provided by qtdemux, unfortunatley it > gives me the wrong sample rate 44.1 instead of 48 and I need to know > that the profile has SBR as this effects my decoder setup. > > How do other AAC decoders deal with this? Do they just parse the raw > data, I cant easily do this as my plugin is for a hardware decoder. > > Any help appreciated, > > Cheers, > > Neil Here is the output from mediainfo: [remco@localhost sample6]$ mediainfo cooper.mp4 General Complete name : cooper.mp4 Format : MPEG-4 Format profile : Base Media / Version 2 Codec ID : mp42 File size : 148 KiB Duration : 24s 645ms Overall bit rate mode : Variable Overall bit rate : 49.1 Kbps Performer : cooper Encoded date : UTC 2006-02-17 19:20:11 Tagged date : UTC 2006-02-17 19:20:16 Writing application : Nero AAC Codec 4.9.9.95 Audio ID : 1 Format : AAC Format/Info : Advanced Audio Codec Format profile : HE-AAC / LC Codec ID : 40 Duration : 24s 645ms Bit rate mode : Variable Bit rate : 48.0 Kbps Maximum bit rate : 51.2 Kbps Channel(s) : 2 channels Channel positions : Front: L R Sampling rate : 44.1 KHz / 22.05 KHz Compression mode : Lossy Stream size : 144 KiB (97%) Language : English Encoded date : UTC 2006-02-17 19:20:11 Tagged date : UTC 2006-02-17 19:20:16 Material_Duration : 24648 Material_Duration_LastFrame : -11 Material_StreamSize : 146949 Please note that the bit rate is 48kb but the sampling rate is 44.1 KHz. Cheers, Remco -- Remco Treffkorn (RT445) HAM DC2XT [hidden email] (831) 685-1201 _______________________________________________ gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
Re: Problems with AAC and qtdemux
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In reply to this post by Neil Jones
On Mon, 2012-03-19 at 15:31 +0000, Neil Jones wrote:
> this is a 48Khz LC-AAC with SBR (ie HE-AAC), looking a this with > qtdemux and fakesink gives: > > > gst-launch -vvv filesrc location=cooper.mp4 ! qtdemux ! fakesink | more > > .... > caps = audio/mpeg, mpegversion=(int)4, framed=(boolean)true, > stream-format=(string)raw, codec_data=(buffer)139056e5a0, > rate=(int)44100, channels=(int)2 > .... > > So as qtdemux gives us raw data (not adts or adif framed) I need to > setup my decoder on the info provided by qtdemux, unfortunatley it > gives me the wrong sample rate 44.1 instead of 48 and I need to know > that the profile has SBR as this effects my decoder setup. > > How do other AAC decoders deal with this? Do they just parse the raw > data, I cant easily do this as my plugin is for a hardware decoder. You can get that information from the "codec_data" buffer in the caps, which is basically codec setup data. It's the same as the "esds" atom in a quicktime/isomp4 container. Cheers -Tim _______________________________________________ gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
Re: Problems with AAC and qtdemux
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In reply to this post by Neil Jones
You can also build ADTS header and attach it with every frame, following link gives information about ADTS header;
http://wiki.multimedia.cx/index.php?title=ADTS
On Mon, Mar 19, 2012 at 9:01 PM, Neil Jones <[hidden email]> wrote: Im trying to play MP4 files with my AAC Decoder but im having problems. Regards, Sudarshan Bisht _______________________________________________ gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
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In reply to this post by Tim-Philipp Müller-2
Cheers for the replies guys,
the codec_data buffer provided in the caps looks promising ( i just assumed this was the address of the first buffer ). This appears to be just an address, can I just dereference this ? are there any buffer ownership issues I need to be aware of ? Cheers Neil On Mon, Mar 19, 2012 at 6:22 PM, Tim-Philipp Müller <[hidden email]> wrote: > On Mon, 2012-03-19 at 15:31 +0000, Neil Jones wrote: > >> this is a 48Khz LC-AAC with SBR (ie HE-AAC), looking a this with >> qtdemux and fakesink gives: >> >> >> gst-launch -vvv filesrc location=cooper.mp4 ! qtdemux ! fakesink | more >> >> .... >> caps = audio/mpeg, mpegversion=(int)4, framed=(boolean)true, >> stream-format=(string)raw, codec_data=(buffer)139056e5a0, >> rate=(int)44100, channels=(int)2 >> .... >> >> So as qtdemux gives us raw data (not adts or adif framed) I need to >> setup my decoder on the info provided by qtdemux, unfortunatley it >> gives me the wrong sample rate 44.1 instead of 48 and I need to know >> that the profile has SBR as this effects my decoder setup. >> >> How do other AAC decoders deal with this? Do they just parse the raw >> data, I cant easily do this as my plugin is for a hardware decoder. > > You can get that information from the "codec_data" buffer in the caps, > which is basically codec setup data. It's the same as the "esds" atom in > a quicktime/isomp4 container. > > Cheers > -Tim > > _______________________________________________ > gstreamer-devel mailing list > [hidden email] > http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
Re: Problems with AAC and qtdemux
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On Tue, 2012-03-20 at 11:05 +0000, Neil Jones wrote:
> the codec_data buffer provided in the caps looks promising ( i just > assumed this was the address of the first buffer ). > > This appears to be just an address, can I just dereference this ? are > there any buffer ownership issues I need to be aware of ? > > > >> caps = audio/mpeg, mpegversion=(int)4, framed=(boolean)true, > >> stream-format=(string)raw, codec_data=(buffer)139056e5a0, > >> rate=(int)44100, channels=(int)2 > >> .... It's not an address. Those are actually 5 bytes in hex notation. You can get to the buffer via: GstStructure *s; const GValue *value; s = gst_caps_get_structure (caps, 0); value = gst_structure_get_value (structure, "codec_data"); if (value != NULL) { GstBuffer *codec_data; const guint8 *data; guint data_size; codec_data = gst_value_get_buffer (value); data = GST_BUFFER_DATA (codec_data); data_size = GST_BUFFER_SIZE (codec_data); gst_util_dump_mem (data, data_size); } Cheers -Tim _______________________________________________ gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
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