[Libav-user] Unable to read frame

[Thanumaiweerakun, Sornrakitch]

Hi,


I have found that if I rearrange the atom moov to the front in the mentioned files (e.g. with qt-faststart), av_read_frame() and avformat_find_stream_info() can process them fine. I am wondering if anyone has faced this mispositioned atom moov problem and if there is a support on this problem or not. As a file, I think libav should be able to search the whole for atom moov easily, but still this problem occurs.


I am trying to use libav with the streaming of mp4 files, so I am finding out how to use libav with this kind of files. If anyone has an idea or has came across this kind of problem before, please do not hesitate to give your opinion.


Regards,

Sornrakitch

________________________________
From: Thanumaiweerakun, Sornrakitch
Sent: Thursday, August 30, 2018 1:57:14 AM
To: libav-user at ffmpeg.org
Subject: Unable to read frame


Hi,


I would like to ask some questions. I am doing a project measuring streaming videos. Currently, I use ffmpeg to get video info and trying to read some frames. I tried using this https://www.ffmpeg.org/doxygen/3.1/avio_reading_8c-example.html with av_read_frame() from ffmpeg's example to try with mp4 files downloaded from youtube and dtube<http://d.tube>. Only videos from dtube generate an error, as follows:


[mov,mp4,m4a,3gp,3g2,mj2 @ 0xed4040] stream 0, offset 0x30: partial file

[mov,mp4,m4a,3gp,3g2,mj2 @ 0xed4040] Could not find codec parameters for stream 0 (Video: h264 (avc1 / 0x31637661), none, 854x480, 1059 kb/s): unspecified pixel format

Consider increasing the value for the 'analyzeduration' and 'probesize' options

[mov,mp4,m4a,3gp,3g2,mj2 @ 0xed4040] Could not find codec parameters for stream 1 (Audio: aac (mp4a / 0x6134706D), 44100 Hz, 2 channels, 127 kb/s): unspecified sample format

Consider increasing the value for the 'analyzeduration' and 'probesize' options

Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'dtube.mp4':

  Metadata:

    major_brand     : isom

    minor_version   : 512

    compatible_brands: isomiso2avc1mp41

    encoder         : Lavf57.56.101

  Duration: 00:06:03.50, bitrate: N/A

    Stream #0:0(eng): Video: h264 (avc1 / 0x31637661), none, 854x480, 1059 kb/s, SAR 1280:1281 DAR 16:9, 29.97 fps, 29.97 tbr, 30k tbn, 30k tbc (default)

    Metadata:

      handler_name    : VideoHandler

    Stream #0:1(eng): Audio: aac (mp4a / 0x6134706D), 44100 Hz, 2 channels, 127 kb/s (default)

    Metadata:

      handler_name    : SoundHandler

[mov,mp4,m4a,3gp,3g2,mj2 @ 0xed4040] stream 0, offset 0x30: partial file

av_read_frame: Invalid data found when processing input


I have already tried with different versions of ffmpeg. I would be appreciated if someone could help me with this.

Regards,
Sornrakitch

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