Mp4 Corruption

nemesis_monkey · Post by **nemesis_monkey** » Mon Apr 30, 2007 1:35 pm

well I have recently got an mp4 player and for some reason all the mp4 files I download seem to be "corrupt", what could be the cause of this

Kariudo · Post by **Kariudo** » Mon Apr 30, 2007 1:44 pm

if you abruptly cut off the internet while downloading, or cut the connection bewtween your player and computer while transfering files it could cause corruption.

it may also be that your downloads aren't compatible with your player, most of em have specific resolutions/codecs/bitrates that they want you to use

Kevmaster · Post by **Kevmaster** » Mon Apr 30, 2007 1:47 pm

uhmn...If ur talking about an portable player like ipod, psp, etc..

...most mp4 player use another mp4 format than the HQ .246 format..uhmn..you need a convertor to convert them to the right format

JudgeHolden · Post by **JudgeHolden** » Mon Apr 30, 2007 3:02 pm

Kevmasterflashdeluxe wrote:uhmn...If ur talking about an portable player like ipod, psp, etc..

...most mp4 player use another mp4 format than the HQ .246 format..uhmn..you need a convertor to convert them to the right format

Exactly, the mp4 the PC users here use, is not standard h264 encodes.

Willen · Post by **Willen** » Tue May 01, 2007 7:19 am

Most likely, the player requires a specific set of resolutions and possibly bitrates for the MP4 files. Not to mention that it may only handle MPEG-4 SP/ASP video, aka. DivX or XviD in a MP4 container. I've even found a few "MP4" players that advertise MPEG-4 playback but only for videos that are in the AVI file format, like most DivX and XviD videos you find on the internet, instead of an actual MP4 file.

The more popular portable video players like the Apple iPod and Sony PSP require MP4 files to follow strict resolution parameters and have certain limits on maximum bitrates. For example, here are the supported formats for the iPod:

Video formats supported:

H.264 video, up to 1.5 Mbps, 640 by 480 pixels, 30 frames per sec., Low-Complexity version of the H.264 Baseline Profile with AAC-LC audio up to 160 Kbps, 48 kHz, stereo audio in .m4v, .mp4, and .mov file formats;

H.264 video, up to 768 Kbps, 320 by 240 pixels, 30 frames per sec., Baseline Profile up to Level 1.3 with AAC-LC audio up to 160 Kbps, 48 kHz, stereo audio in .m4v, .mp4, and .mov file formats;

MPEG-4 video, up to 2.5 Mbps, 640 by 480 pixels, 30 frames per sec., Simple Profile with AAC-LC audio up to 160 Kbps, 48 kHz, stereo audio in .m4v, .mp4, and .mov file formats

For the PSP:

You can play files of the following types on the PSP™ system.

Memory Stick™ Video Format, MP4
- MPEG-4 Simple Profile (AAC) (all versions):
MPEG-4 SP, up to 768 kbps (1.5 Mbps with a file header hack), 320 by 240 pixels or 368 by 208 pixels (or any combination totaling 76,800 pixels), 30 or 15 frames per sec., Simple Profile with AAC-LC audio up to 128 Kbps, 24 kHz, stereo audio in .mp4 file format.

- H.264/MPEG-4 AVC Baseline Profile (AAC) (firmware version 2.00 and higher):
AVC (H.264), up to 768 kbps, 320 by 240 pixels or 368 by 208 pixels (or any combination totaling 76,800 pixels), 4:3 or 16:9 aspect ratio, 30 frames per sec.*, Baseline Profile up to Level 1.3 with AAC-LC audio up to 128 Kbps, 48 kHz, stereo audio in .mp4 file format.

*Version 2.60 and later firmware adds support for 24 frames per second (NTSC FILM) video AVC format files. Version 2.80 adds support for H.264/MPEG-4 AVC Main Profile (CABAC) (AAC) up to Level 2.1, 25 fps (PAL) video, flexible file naming, and the use of the "VIDEO" folder.

New for 3.30 firmware: The following types of files can now be played in the "VIDEO" folder.
– MPEG-4/H.264 AVC Main Profile (AVC CABAC) video files of the following sizes:
720 X 480, 352 X 480, or 480 X 272.

AVI format (version 3.0 or higher)
- Motion JPEG (Linear PCM)
- Motion JPEG (μ-Law)

Zero1 · Post by **Zero1** » Wed May 02, 2007 5:09 pm

JudgeHolden wrote:
Kevmasterflashdeluxe wrote:uhmn...If ur talking about an portable player like ipod, psp, etc..

...most mp4 player use another mp4 format than the HQ .246 format..uhmn..you need a convertor to convert them to the right format
Exactly, the mp4 the PC users here use, is not standard h264 encodes.

The guide I wrote, and the software Zarxrax coded create perfectly standard H.264 encodes. In fact if you use x264 and MP4, it's still perfectly standard.

Perfectly standard, just too complex for iPods and stuff to play due to their low CPU power. A H.264 encode would only be non standard if you stored it in AVI, MKV or OGM, since MPEG only specify MPEG-2 Transport steams and MP4 files. You may also be able to store it in MPEG program streams (MPG), but it's not common and not recommended.

Just because a certain hardware device does not play it, does not mean there is a problem with the file, for example I can create a perfectly standard file that won't play in quicktime because quicktime only has a partial decoder; which is Apple's fault, not mine or anyone elses.

Unlike MPEG-1 which was regularly used for 352x240/288 encodes at 1.15mbps, H.264 scales from resolutions as small as mobile phones (128x96) up to studio quality at 4096x4096, so of course you can't expect to play a certain encode on anything.

JudgeHolden · Post by **JudgeHolden** » Wed May 02, 2007 5:16 pm

Zero1 wrote:
JudgeHolden wrote:
Kevmasterflashdeluxe wrote:uhmn...If ur talking about an portable player like ipod, psp, etc..

...most mp4 player use another mp4 format than the HQ .246 format..uhmn..you need a convertor to convert them to the right format
Exactly, the mp4 the PC users here use, is not standard h264 encodes.
The guide I wrote, and the software Zarxrax coded create perfectly standard H.264 encodes. In fact if you use x264 and MP4, it's still perfectly standard.

Perfectly standard, just too complex for iPods and stuff to play due to their low CPU power. A H.264 encode would only be non standard if you stored it in AVI, MKV or OGM, since MPEG only specify MPEG-2 Transport steams and MP4 files. You may also be able to store it in MPEG program streams (MPG), but it's not common and not recommended.

Just because a certain hardware device does not play it, does not mean there is a problem with the file, for example I can create a perfectly standard file that won't play in quicktime because quicktime only has a partial decoder; which is Apple's fault, not mine or anyone elses.

Unlike MPEG-1 which was regularly used for 352x240/288 encodes at 1.15mbps, H.264 scales from resolutions as small as mobile phones (128x96) up to studio quality at 4096x4096, so of course you can't expect to play a certain encode on anything.

So, my question is then, why on a mac is it a crap shoot as to wether an pc encoded mp4 will play in VLC? Often I have to try 3 different players to find one that might play the video, and there are times when it won't play at all. Yet, if I encode an Mp4 off my Mac, it will play on a PC just fine ... Where is the disconnect? I know this is an issue with most mac users on the site.

Zero1 · Post by **Zero1** » Wed May 02, 2007 6:20 pm

Are we talking about playback performance and lagging, or just flat out not playing?

I've never had a problem at all, not with VLC, FFDShow or CoreAVC.

It may also be that the VLC you are using is ancient and incomplete, you can get a recent build here to try:
http://nightlies.videolan.org/build/macosx/?C=M;O=D

This is for Mac OSX Power PC, you can go here to find other builds
http://nightlies.videolan.org/

The other thing is are you talking about H.264 in MP4 or MKV? Because I know MKV support is bad on VLC.

JudgeHolden · Post by **JudgeHolden** » Wed May 02, 2007 7:01 pm

It all depends on the video. One might sutter in VLC and then play great in mplayer or may not play at all in one and play in the other. Then there are Krat's videos that will play in every player perfectly. I downloaded the nightly build for VLC, and nothing has changed, same issues. To me it looks more like inconistant implementation of the codec. Like some people trying to do to much and not really undersatnding what they are doing.

Anyway, if you are on a PC, you would never see these issues.

JudgeHolden · Post by **JudgeHolden** » Wed May 02, 2007 7:22 pm

I thought I should add that they are mp4. Oh, and mplayer seems to be the more relaible player for mp4s on a Macs, so it could also be a problem with VLC. Either way it is frustrating.