[FFmpeg-devel] There may be a bug for .mp4 reader.
yhe at matrox.com
Mon Apr 1 22:57:17 EEST 2019
On 04/01/2019 01:42 PM, Devin Heitmueller wrote:
> Hello Yufei,
>> On Apr 1, 2019, at 1:21 PM, Yufei He <yhe at matrox.com> wrote:
>> There may be a bug for .mp4 reader.
>> On decoding some ntsc mp4 files with my h.264 codec, from actvx I received,
>> avctx->framerate.den is 100
>> avctx->framerate.num is 2997
>> avctx->pkt_timebase.num is 1
>> avctx->pkt_timebase.den is 2997
>> Duration of every packet I received from ff_decode_get_packet(avctx, &pkt) is 100, which means it's a encoded frame. But actually, it's a encoded field, it's duration should be 50.
> Libavcodec doesn’t have any support for delivering individual fields. Decoders are expected to reassemble fields into frames before providing them back to callers.
> Presumably this is some sort of PAFF encoded stream? Does it decode properly when using the software h.264 decoder?
The data decoded is in frames, my problem is the source compressed data:
it could be a field or a frame depending on files, every packet for
compressed data has duration and it should be accurate, I use it
directly instead of parsing it again. it seems it's not correct for some
.mp4 files. and I find it's not correct for xavc mxf long gop files
today, though xavc intra files are good.
> Devin Heitmueller - LTN Global Communications
> dheitmueller at ltnglobal.com
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