[FFmpeg-devel] [PATCH] avformat/dashenc: Disable writing CODECS tag for HEVC streams

[Jeyapal, Karthick]

On 10/21/18 2:28 PM, Hendrik Leppkes wrote:
> On Sun, Oct 21, 2018 at 10:41 AM Karthick J <kjeyapal at akamai.com> wrote:
>>
>> For HEVC streams, only the FourCC tag is written without profile, level etc.,
>> This is breaking playout support in native Safari.
>> Native Safari playout expects the full info in CODECS tag or None at all.
>
> Generating the full string shouldn't be that impossible for HEVC
> either, why not go that more complete route?
Two reasons:
1. I was not sure what is the right format of that string. I saw some examples, like hvc1.2.4.L123.B0. But I didn't know what that meant.
If somebody here could provide some explanation or the relevant spec, I will hold off this patch and would definitely try implementing it.

2. I heard recently in a demuxed talk that for 2K and 4K resolution Apple clients don't playout properly even when properly constructed CODEC tag is there(hvc1.2.4.L153).
But they played properly without a CODEC tag. https://www.twitch.tv/videos/323919819 , Seek to 42:30 for the relevant info.

For the above two reasons, I assumed it is going to be a time-consuming job. Hence, I decided to atleast restore the earlier status for HEVC, so that we don't break anything that was working properly earlier.
>
> - Hendrik
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