Isn't decodebin2 good enough to demux/decode any kind of incoming video

emojo support at emojo.in
Mon May 14 03:01:02 PDT 2012


Hi All,

I am trying to create a pipeline for basically streaming an mp4 file via RTP
stream (DSS or gst-rtsp-server) and below are the commands i triggered for
two different mp4 files i have -

gst-launch -vvv filesrc location=/home/ubuntu/3d.mp4 ! qtdemux name=d d. !
queue ! rtph264pay pt=96 name=pay0 d. ! queue ! rtpmp4apay pt=97 name=pay1

gst-launch -vvv filesrc location=/home/ubuntu/sample.mp4 ! decodebin2 name=d
d. ! queue ! rtph264pay pt=96 name=pay0 d. ! queue ! rtpmp4apay pt=97
name=pay1

both of the above files were able to generate the desired output but my
query is why i had to use different demixers for two mp4 files (below are
the mdia info for both the files) also i saw some where that decodebin2 is a
sort of global demuxer/decoder which can be used for almost any format
(please correct me if i am wrong here) then why its not able to stream both
the files.

media info of 3d.mp4 -
General
Complete name                            : D:\emojo\sample_vids\3d.mp4
Format                                   : MPEG-4
Format profile                           : Base Media / Version 2
Codec ID                                 : mp42
File size                                : 253 KiB
Duration                                 : 8s 83ms
Overall bit rate mode                    : Variable
Overall bit rate                         : 257 Kbps
Encoded date                             : UTC 2010-07-19 14:16:50
Tagged date                              : UTC 2010-07-19 14:16:50
gsst                                     : 0
gstd                                     : 8590
gssd                                     : B4A7DDA83MM1336570568929089
gshh                                     :
o-o.preferred.fra07t11.v3.cache5.c.youtube.com

Video
ID                                       : 2
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : Baseline at L2.1
Format settings, CABAC                   : No
Format settings, ReFrames                : 1 frame
Format settings, GOP                     : M=1, N=12
Codec ID                                 : avc1
Codec ID/Info                            : Advanced Video Coding
Duration                                 : 8s 83ms
Bit rate                                 : 251 Kbps
Maximum bit rate                         : 948 Kbps
Width                                    : 480 pixels
Height                                   : 360 pixels
Display aspect ratio                     : 4:3
Frame rate mode                          : Constant
Frame rate                               : 24.000 fps
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Bits/(Pixel*Frame)                       : 0.060
Stream size                              : 247 KiB (98%)
Title                                    : (C) 2007 Google Inc. v08.13.2007.
Encoded date                             : UTC 2010-07-19 14:16:50
Tagged date                              : UTC 2010-07-19 14:16:50

Audio
ID                                       : 1
Format                                   : AAC
Format/Info                              : Advanced Audio Codec
Format profile                           : LC
Codec ID                                 : 40
Duration                                 : 8s 80ms
Bit rate mode                            : Variable
Bit rate                                 : 3 096 bps
Maximum bit rate                         : 3 240 bps
Channel(s)                               : 2 channels
Channel positions                        : Front: L R
Sampling rate                            : 44.1 KHz
Compression mode                         : Lossy
Stream size                              : 3.06 KiB (1%)
Title                                    : (C) 2007 Google Inc. v08.13.2007.
Encoded date                             : UTC 2010-07-19 14:16:50
Tagged date                              : UTC 2010-07-19 14:16:50

media info for sample.mp4 -

General
Complete name                            : D:\emojo\sample_vids\sample.mp4
Format                                   : MPEG-4
Format profile                           : Base Media
Codec ID                                 : isom
File size                                : 11.2 MiB
Duration                                 : 3mn 19s
Overall bit rate mode                    : Variable
Overall bit rate                         : 471 Kbps

Video
ID                                       : 1
Format                                   : MPEG-4 Visual
Format profile                           : Simple at L3
Format settings, BVOP                    : No
Format settings, QPel                    : No
Format settings, GMC                     : No warppoints
Format settings, Matrix                  : Default (H.263)
Codec ID                                 : 20
Duration                                 : 3mn 19s
Bit rate                                 : 425 Kbps
Width                                    : 320 pixels
Height                                   : 240 pixels
Display aspect ratio                     : 4:3
Frame rate mode                          : Constant
Frame rate                               : 20.000 fps
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Compression mode                         : Lossy
Bits/(Pixel*Frame)                       : 0.277
Stream size                              : 10.1 MiB (90%)
Writing library                          : XviD 1.1.2 (UTC 2006-11-01)

Audio
ID                                       : 2
Format                                   : AAC
Format/Info                              : Advanced Audio Codec
Format profile                           : LC
Codec ID                                 : 40
Duration                                 : 3mn 19s
Bit rate mode                            : Variable
Bit rate                                 : 42.8 Kbps
Channel(s)                               : 2 channels
Channel positions                        : Front: L R
Sampling rate                            : 32.0 KHz
Compression mode                         : Lossy
Stream size                              : 1.01 MiB (9%)

Thanks,
AJ

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