[FFmpeg-user] MPEG-4/WAV container for quick A/V sync tweaking

[Olivier Guilyardi]

On 04/18/2011 11:15 PM, Andrew Berg wrote:

> That's ambiguous, but I think FFmpeg reports AVC/H.264 as h264 instead
> of mpeg4 (which means your original is MPEG-4 Part 2). I'm pretty sure
> 3GP supports MPEG-4 Part 2. You can always use MediaInfo to find out
> exactly what you have.

mediainfo says:

General
Complete name                    : /tmp/VID_20110418_110132.3gp
Format                           : MPEG-4
Format profile                   : 3GPP Media Release 4
Codec ID                         : 3gp4
File size                        : 1.81 MiB
Duration                         : 7s 437ms
Overall bit rate                 : 2 045 Kbps

Video
ID                               : 1
Format                           : MPEG-4 Visual
Format settings, BVOP            : Yes
Format settings, QPel            : No
Format settings, GMC             : No warppoints
Format settings, Matrix          : Default (H.263)
Codec ID                         : 20
Duration                         : 7s 437ms
Bit rate mode                    : Variable
Bit rate                         : 2 042 Kbps
Nominal bit rate                 : 2 169 Kbps
Maximum bit rate                 : 2 359 Kbps
Width                            : 720 pixels
Height                           : 480 pixels
Display aspect ratio             : 3:2
Frame rate mode                  : Variable
Frame rate                       : 24.069 fps
Minimum frame rate               : 22.727 fps
Maximum frame rate               : 24.390 fps
Standard                         : NTSC
Color space                      : YUV
Bit depth                        : 8 bits
Scan type                        : Progressive
Compression mode                 : Lossy
Bits/(Pixel*Frame)               : 0.245
Stream size                      : 1.81 MiB (100%)
Language                         : English


So it seems liks it's H.263. Actually, I can also get H.264. I need to be able
to handle both.

>> Can I use FFmpeg from the command line to:

> I recommend using MP4Box for this. Of course, if you don't specify an
> offset (or specify the wrong offset) the first time you mux, you will
> need to rewrite the entire file. MP4Box is great for producing compliant
> containers, but it requires rewriting or remuxing for damn near everything.

Okay, remuxing is not an option. But since I would obtain the file from mp4box,
it's not as if I was working on some random mp4 file with weird headers and
such. So maybe that I could code something from scratch to tweak the sync offset
quickly without using mp4box again after initial muxing.

> In any case, Matroska will work if it can specify an offset.

Matroska looks more and more attractive to me. It would require quite a lot of
extra work in my very case, but it seems like a great format. I especially love
the fact that it's designed to ease editing, which could be useful for me in the
future.

But, I've google all combinations of matroska, AV, sync, offset, timecode etc..
And I couldn't find anything. Any clue?

--
  Olivier