[FFmpeg-devel] [PATCH] avcodec/dvdec: add frame threads

Tobias Rapp t.rapp at noa-archive.com
Thu Apr 18 13:13:23 EEST 2019

On 18.04.2019 11:40, Michael Niedermayer wrote:
> On Thu, Apr 18, 2019 at 10:30:49AM +0200, Paul B Mahol wrote:
>> On 4/18/19, Michael Niedermayer <michael at niedermayer.cc> wrote:
>>> On Thu, Apr 18, 2019 at 01:19:58AM +0200, Michael Niedermayer wrote:
>>>> On Wed, Apr 17, 2019 at 06:16:39PM +0200, Paul B Mahol wrote:
>>>>> Signed-off-by: Paul B Mahol <onemda at gmail.com>
>>>>> ---
>>>>>   libavcodec/dvdec.c | 19 ++++++++++---------
>>>>>   1 file changed, 10 insertions(+), 9 deletions(-)
>>>> Is this intended to be 100% same output ?
>>>> I have a few cases that produce differences. Dont have a good testcase
>>>> though
>>>> ./ffmpeg -i ~/tickets/1589/A1590.dv avi-b.avi
>>>> produces different output.
>>>> oddly -f framecrc produces the same output
>>>> not sure this is a problem or not the input file may have issues
>>> heres another testcase:
>>> ./ffmpeg -i ~/tickets/2390/dv_cut.dv aviavi2.avi
>>> [...]
>> This is because audio is muxed differently.
>> This bug have nothing to do with this patch.
> iam not sure thats the case. Looking at this again now in the morning
> VPRP is different and the muxer receives a different par->field_order
> (0 vs. 5). I dont think audio should afect the video field_order

That might be caused by frame-threading in general and not explicitly by 
the dv decoder. Have experienced field_order information not being 
reliably forwarded to the muxer in ffmpeg before. Seems sometimes the 
encoder settings are updated too late to be picked up by the muxer when 
writing header information.


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