[FFmpeg-devel] [PATCH] avformat/mpegts: initialize max_packet_size when sub-demuxer

Gyan Doshi ffmpeg at gyani.pro
Tue Feb 8 13:03:26 EET 2022



On 2022-02-07 09:34 am, Gyan Doshi wrote:
>
>
> On 2022-02-07 03:59 am, Marton Balint wrote:
>>
>>
>> On Sat, 5 Feb 2022, Gyan Doshi wrote:
>>
>>> bca30570d2 added a user option to set max_packet_size replacing
>>> a hardcoded value. This had a side-effect of leaving the field
>>> set to 0 when packet demuxing is carried out from another demuxer
>>> using avpriv functions, which could lead to demux failure.
>>>
>>> Hardcoded max_packet_size inside avpriv_mpegts_parse_open to
>>> 2048000 to avoid this. Value chosen to be 10x that of default value
>>> to accommodate large payloads.
>>
>> I don't understand why the default is different from the normal 
>> mpegts case. Large payloads can happen there as well, and previously 
>> it was assumed that splitting is OK, because it will be parsed anyway.
> The option was added because MPEG-TS allows any codec to be carried as 
> a private stream and when demuxing that, the parser isn't inserted, 
> even when forcing a decoder, hence the need to not have split packets. 
> In this case, the user can't tune the value, so I went with an 
> expansive one.

Plan to push tomorrow.

Regards,
Gyan


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