[FFmpeg-devel] [PATCH] avformat/mpegts: Add AVFMT_FLAG_ALLOW_CODEC_CHANGES (v2)

[Scott Theisen]

On 2025/07/01 01:39, Pavel Koshevoy wrote:
> On Mon, Jun 30, 2025, 21:46 Michael Niedermayer<michael at niedermayer.cc>
> wrote:
>
>> On Mon, Jun 30, 2025 at 07:32:36PM -0600, Pavel Koshevoy wrote:
>>> On Mon, Jun 30, 2025 at 3:46 PM Scott Theisen <
>>> scott.the.elm-at-gmail.com at ffmpeg.org> wrote:
>>>
>>>> On 2025/06/29 23:55, Pavel Koshevoy wrote:
>>>>> Make midstream AVStream.codecpar updates optional and disabled
>>>>> by default, so that avformat API clients can enable this feature
>>>>> explicitly when they add support for midstream codec changes.
>>>> Is this signaled in any way or is the client expected to check if
>>>> codecpar has changed?
>>>>
>>> The client is expected to check codecpar for changes ...
>> What performance impact does this have ?
>>
> In my player?  None that I cared to measure

MPEG-TS and MPEG-PS can have a new PMT (TS) or PSM (PS) at any time to 
do any of the following: modifying current streams, adding new streams, 
or removing streams.  Therefore, to fully support those containers, you 
need to check if the version numbers have changed anyways (or be 
notified by a callback).

libavformat/mpeg.c does not use the program_stream_map_version.

Regards,

Scott Theisen