Playing a VOB file that uses the AC3 audio codec

jimheath — Mon, 14 Apr 2014 18:07:08 GMT

Does anyone know how to play a VOB file that uses the AC3 audio codec using gstreamer? I'm testing with gplay on our custom board based on Boundary Device's Nitrogen6X (chip: i.MX6Q) using the latest Timesys BSP. The video works fine but gstreamer is showing the following error with the audio:

get GST_MESSAGE_ELEMENT missing-plugin, type=(string)decoder, detail=(GstCaps)audio/x-ac3, framed=(boolean)true, alignment=(string)frame, name=(string)"AC-3\ \(ATSC\ A/52\)\ decoder";

If I look for AC3 support using gst-inspect:

# gst-inspect | grep -i AC3

typefindfunctions: audio/x-ac3: ac3, eac3

rtp: rtpac3depay: RTP AC3 depayloader

rtp: rtpac3pay: RTP AC3 audio payloader

audioparsers: ac3parse: AC3 audio stream parser

beep.imx: ac3: ac3

beep.imx: 3ca: ac3

beep.imx: beepdec.ac3: AC3 decoder

So it looks like there is support for decoding AC3 audio. Here are the versions of gstreamer and plugin libraries I'm using:

gstreamer 0.10.36, gst-fsl-plugin 3.5.7-1.0, gst-plugins-bad 0.10.23, gst-plugins-base 0.10.36, gst-plugins-gl 0.10.3.1, gst-plugins-good 0.10.31

Thanks,

Jim

Re: Playing a VOB file that uses the AC3 audio codec

jimheath — Mon, 14 Apr 2014 20:40:39 GMT

I added the liba52 (shows as a52dec in the Timesys desktop factory menu) library to my build and can now play VOB files and hear the audio on most of the VOB files I have. Some VOB files that still have a problem, I see the following when playing with gplay:

Track 01 [audio_000001] Enabled

ppid: 0, ppid 1

Duration: 1:02:02.528000000

Language: und

Mime:

audio/x-ac3, channels=(int)6, rate=(int)48000, bitrate=(int)448000, framed=(bool

ean)true

Track 02 [audio_000002] Enabled

ppid: 0, ppid 2

Duration: 1:02:02.528000000

Language: und

Mime:

audio/x-ac3, channels=(int)6, rate=(int)48000, bitrate=(int)448000, framed=(bool

ean)true

Track 03 [audio_000003] Enabled

ppid: 0, ppid 3

Duration: 1:02:02.464000000

Language: und

Mime:

audio/x-ac3, channels=(int)2, rate=(int)48000, bitrate=(int)192000, framed=(bool

ean)true

Track 04 [audio_000004] Enabled

ppid: 0, ppid 4

Duration: 1:02:02.464000000

Language: und

Mime:

audio/x-ac3, channels=(int)2, rate=(int)48000, bitrate=(int)192000, framed=(bool

ean)true

FOUND GST_MESSAGE_TAG!

codec: MPEG2

language code: und

bitrate: 9800000

FOUND GST_MESSAGE_TAG!

container format: MPEG

FOUND GST_MESSAGE_TAG!

codec: AC3

language code: und

bitrate: 448000

FOUND GST_MESSAGE_TAG!

codec: AC3

language code: und

bitrate: 448000

FOUND GST_MESSAGE_TAG!

codec: AC3

language code: und

bitrate: 192000

FOUND GST_MESSAGE_TAG!

codec: AC3

language code: und

bitrate: 192000

No accelerated IMDCT transform found

FOUND GST_MESSAGE_TAG!

audio codec: Dolby Digital (AC-3)

bitrate: 448000

FOUND GST_MESSAGE_TAG!

audio codec: Dolby Digital (AC-3)

bitrate: 192000

FOUND GST_MESSAGE_TAG!

audio codec: Dolby Digital (AC-3)

bitrate: 192000

MFW_GST_V4LSINK_PLUGIN 3.0.7 build on Apr 10 2014 11:59:31.

[INFO] bitstreamMode 1, chromaInterleave 1, mapType 0, tiled2LinearEnable 0

FOUND GST_MESSAGE_TAG!

audio codec: Dolby Digital (AC-3)

bitrate: 448000

>>V4L_SINK: Actually buffer status:

hardware buffer : 10

software buffer : 0

get GST_MESSAGE_ELEMENT playbin2-stream-changed, uri=(string)file:///media/testvideo.VOB;

FOUND GST_MESSAGE_TAG!

minimum bitrate: 448000

maximum bitrate: 448000

full screen size:1280x720

I don't know if it has anything to do with there being multiple audio tracks with these particular VOB files, but sometimes I get audio, sometimes nothing but some crackling noises every once in awhile and other times the audio track is different as though a random one is being chosen. Is the "No accelerated IMDCT transform found" message just a warning? I'm seeing this on any VOB file using AC3 audio encoding.

Jim

topic Re: Playing a VOB file that uses the AC3 audio codec in i.MX Processors

Playing a VOB file that uses the AC3 audio codec

Re: Playing a VOB file that uses the AC3 audio codec