On 12.05.2017 11:33, Eric Beuque wrote:
Hi,i'm not really sure but i think a found a bug in the avi decoder of avformat. In the following function of the avidec.c: static int avi_read_header(AVFormatContext *s) { ... switch (tag) { ... case MKTAG('s', 't', 'r', 'f'): /* stream header */ if (!size) break; if (stream_index >= (unsigned)s->nb_streams || avi->dv_demux) { avio_skip(pb, size); } else { ... switch (codec_type) { ... default: st->codec->codec_type = AVMEDIA_TYPE_DATA; st->codec->codec_id = AV_CODEC_ID_NONE; st->codec->codec_tag = 0; avio_skip(pb, size); break; } } break; ... } If the codec_type is AVMEDIA_TYPE_DATA, but the format is empty (size=0) (which i think is allowed), then the codec_id is not set to AV_CODEC_ID_NONE. This will generate a trace when calling the avformat_find_stream_info: "Could not find codec parameters for stream 1 (Unknown: none): unknown codec Consider increasing the value for the 'analyzeduration' and 'probesize' options" I'm not really sure about he AVI spec if the format is mandatory or not, but i think there is a bug.
According to the document at https://msdn.microsoft.com/en-us/library/windows/desktop/dd318189(v=vs.85).aspx the "strf" chunk is mandatory but the data is only specified for audio/video streams so indeed it might be possible that a chunk size of 0 occurs for generic data streams.
Regards, Tobias _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
