[mythtv-users] Status of ffmpeg 4.4.1

[Klaas de Waal]

On Sat, 6 Nov 2021 at 14:42, Peter Bennett <pb.mythtv at gmail.com> wrote:

>
> On 11/6/21 9:02 AM, Klaas de Waal wrote:
>
>
>
> On Fri, 5 Nov 2021 at 22:49, Klaas de Waal <klaas.de.waal at gmail.com>
> wrote:
>
>>
>>
>>
>> On Fri, 5 Nov 2021 at 21:43, Peter Bennett <pb.mythtv at gmail.com> wrote:
>>
>>>
>>> On 11/5/21 3:17 PM, Klaas de Waal wrote:
>>>
>>>
>>>
>>> On Wed, 3 Nov 2021 at 20:30, Peter Bennett <pb.mythtv at gmail.com> wrote:
>>>
>>>> Most things are working with ffmpeg 4.4.1 in the devel/ffmpeg-resync
>>>> branch
>>>>
>>>> What is not working:
>>>>
>>>> - Audio "upconvert stereo to 5.1 sound" when playing a video with
>>>> stereo
>>>> sound - error message and no audio playback .
>>>>
>>>> - Speedup / slowdown when playing a video with dolby 5.1 audio - error
>>>> message and no audio playback .
>>>>
>>>> - Report from John Pilkington that an existing bug with edit markers
>>>> and
>>>> step lengths now reacts slightly differently - I don't know if it is
>>>> better or worse with the new ffmpeg.
>>>>
>>>> I am looking into the 5.1 audio issues.
>>>>
>>>> Peter
>>>>
>>>>
>>>> Hi Peter,
>>>
>>> As mentioned in the mythtv-dev mailing list, there are with the new
>>> FFmpeg often blocking artifacts when starting playback and when jumping
>>> forward and backward.
>>> This happens also on recordings made with the old FFmpeg so it looks to
>>> me like a playback-only issue.
>>> I do see this on my cable TV recordings which are H264, 1080i interlaced
>>> 50/25 frames per second, both HD and SD.
>>> I do NOT see this on Bluray rips which are 24p.
>>> I also do not see this on recordings with MPEG2 video coding, only on
>>> H264.
>>>
>>> Hope you can have a look into this also,
>>>
>>> Thanks,
>>> Klaas.
>>>
>>>
>>>
>>> I am not able to reproduce this on the devel/ffmpeg-resync branch. I
>>> tried with NVDEC and with OpenGL playback profiles. Which playback profile
>>> are you using?
>>>
>>>
>>>  Hi Peter,
>>
>> Looks like it happens with VDPAU only. NVDEC, OpenGL and VAAPI (that on
>> Intel hardware) are OK.
>> So the failing combination is VDPAU/H264/interlaced.
>>
>> Tested some more on other recordings and there are also blocking
> artifacts with NVDEC, but less pronounced and also sometimes the stream
> makes a difference. If it is difficult to reproduce I can create a ticket
> for this and attach photographs and clips.
>
> Thanks,
> Klaas.
>
>
>
> _______________________________________________
>
> Hi Klaas
>
> I do not have any H264 interlaced recordings. On Comcast we get MPEG2
> interlaced and H264 progressive. There is a known problem with MPEG2 and
> both NVDEC and VDPAU, also NVidia shield where there are frequent
> pixelations while watching MPEG2, if the stream is highly compressed as
> some USA channels are. This has been around for many years and NVidia seem
> to have no plans to fix it.
>
> I tried with H264 progressive recordings and I do not see any problem with
> VDPAU either.
>
> Maybe you can send a sample H260 interlaced recording. It will have to be
> long enough for me to perform skips, if that is the only way to see the
> problem. What number of seconds do you have for skip ahead and skip back?
>
>
> This is a fragment with the first 100MB of a recent recording, H264 full
HD interlaced.
https://drive.google.com/file/d/14Z5lsY37wgr5vuL7bg7CyDDO-wg0SWIx/view?usp=sharing

Playing from the start already gives blocking artifacts, as shown in the
following link
https://drive.google.com/file/d/1UA_m9gEkcrhTe_KfKfTkgKT_MdNDknyL/view?usp=sharing
This is a screenshot taken immediately after the start of playback at the
beginning of the file.
Jumping is configured here for 45 seconds forward and 15 seconds backward
but it should not matter for reproducing.

FYI, Here on my local cable all HD channels are 1080 interlaced, all SD
channels are MPEG2 interlaced. The MPEG2 recordings play OK.
Bluray, 24p, plays OK. I can also receive OTA a 1080 progressive with H265
coding. This also plays OK.
I use Nvidia GT1030 cards for playback; in the living room on Ubuntu
18.something and the development system on Fedora 35.

I do hope the links do work.

Thanks,
Klaas.
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