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I've a problem while merging two h.264/MP4 files with the same parameters except length.

I'm merging by mp4box -cat .... After that, video players behave strangely: If I drag time slider closer to the end of file it resets to restart the video and sometimes, players are show the incorrect video file length.

Also there is a problem with audio sync.

Input file sample parameters:

* Movie Info *
Timescale 90000 - Duration 00:15:00.214
Fragmented File no - 2 track(s)
File suitable for progressive download (moov before mdat)
File Brand mp42 - version 0
Created: GMT Thu Jun 7 23:31:52 2012

File has root IOD (9 bytes)
Scene PL 0xff - Graphics PL 0xff - OD PL 0xff
Visual PL: ISO Reserved Profile (0x7f)
Audio PL: High Quality Audio Profile @ Level 2 (0x0f)
No streams included in root OD

iTunes Info:

Encoder Software: HandBrake 0.9.6 2012022800

Track # 1 Info - TrackID 1 - TimeScale 90000 - Duration 00:14:59.858
Media Info: Language "Undetermined" - Type "vide:avc1" - 21576 samples
Visual Track layout: x=0 y=0 width=853 height=480
MPEG-4 Config: Visual Stream - ObjectTypeIndication 0x21
AVC/H264 Video - Visual Size 864 x 480
AVC Info: 1 SPS - 1 PPS - Profile Main @ Level 3
NAL Unit length bits: 32
Pixel Aspect Ratio 80:81 - Indicated track size 853 x 480
Self-synchronized

Track # 2 Info - TrackID 2 - TimeScale 44100 - Duration 00:15:00.214
Media Info: Language "English" - Type "soun:mp4a" - 38769 samples
MPEG-4 Config: Audio Stream - ObjectTypeIndication 0x40
MPEG-4 Audio MPEG-4 Audio AAC LC - 2 Channel(s) - SampleRate 44100
Synchronized on stream 1

Output:

* Movie Info *
Timescale 90000 - Duration 00:29:24.136
Fragmented File no - 3 track(s)
File suitable for progressive download (moov before mdat)
File Brand isom - version 1
Created: GMT Thu Jun 28 19:40:39 2012

File has root IOD (9 bytes)
Scene PL 0xff - Graphics PL 0xff - OD PL 0xff
Visual PL: AVC/H264 Profile (0x15)
Audio PL: AAC Profile @ Level 2 (0x29)
No streams included in root OD

Track # 1 Info - TrackID 1 - TimeScale 90000 - Duration 00:19:36.968
Media Info: Language "Undetermined" - Type "vide:avc1" - 28219 samples
Visual Track layout: x=0 y=0 width=1024 height=576
MPEG-4 Config: Visual Stream - ObjectTypeIndication 0x21
AVC/H264 Video - Visual Size 1024 x 576
AVC Info: 1 SPS - 1 PPS - Profile Main @ Level 3.1
NAL Unit length bits: 32
Pixel Aspect Ratio 1:1 - Indicated track size 1024 x 576
Self-synchronized

Track # 2 Info - TrackID 2 - TimeScale 44100 - Duration 00:29:24.136
Media Info: Language "English" - Type "soun:mp4a" - 75975 samples
MPEG-4 Config: Audio Stream - ObjectTypeIndication 0x40
MPEG-4 Audio MPEG-4 Audio AAC LC - 2 Channel(s) - SampleRate 44100
Synchronized on stream 1

Track # 3 Info - TrackID 3 - TimeScale 90000 - Duration 00:09:46.503
Media Info: Language "Undetermined" - Type "vide:avc1" - 14062 samples
Visual Track layout: x=0 y=0 width=1280 height=720
MPEG-4 Config: Visual Stream - ObjectTypeIndication 0x21
AVC/H264 Video - Visual Size 1280 x 720
AVC Info: 1 SPS - 1 PPS - Profile Main @ Level 3.1
NAL Unit length bits: 32
Pixel Aspect Ratio 1:1 - Indicated track size 1280 x 720
Synchronized on stream 1

And I do not understand: Why do I have 2 video tracks in the output?

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migrated from stackoverflow.com Jul 16 '12 at 20:23

This question came from our site for professional and enthusiast programmers.

1 Answer 1

Your video streams have different frame sizes.

The first one is 1024x576 (seems like PAL 576 interlaced), while the second one is 1280x720 (HD 720 progressive).

These two probably weren't meant to work together anyway, and this would explain the errors you're seeing.

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