[FFmpeg-devel] [RFC] Private streams in MPEG PS

Jai Menon jmenon86
Wed May 27 22:08:56 CEST 2009


On Wed, May 27, 2009 at 8:04 PM, Baptiste Coudurier
<baptiste.coudurier at gmail.com> wrote:
> On 5/27/2009 12:52 PM, Jai Menon wrote:
>> On Wed, May 27, 2009 at 6:22 PM, Baptiste Coudurier
>> <baptiste.coudurier at gmail.com> wrote:
>>> Hi,
>>>
>>> On 5/27/2009 11:00 AM, Jai Menon wrote:
>>>> Hi,
>>>>
>>>> I'm becoming increasingly suspicious of this check in lavf/mpeg.c:370 -
>>>>
>>>> ? 4093 ? ? ? ?mru ? ? if (startcode == PRIVATE_STREAM_1 &&
>>>> !m->psm_es_type[startcode & 0xff]) {
>>>>
>>>> ? ? ? ? ? ? ?^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>>>
>>>> Looking at issue 1122 and 725 on roundup, ?I'm inclined to believe
>>>> that a lot of files out there don't have a program stream map (which I
>>>> didn't back when issue 725 was reported). Removing this check actually
>>>> would solve both 1122 and 725 without the need for the fix commited in
>>>> r17150.
>>> Humm, pes_es_type should be init to 0 anyway, if file have no program
>>> stream map. Isn't the problem that psm_es_type is wrongly set ?
>>
>> PSM ES type is set to 0x81 which is correct for both ac3 tracks. The
>> problem is that es_id (which should be unique by current demuxer
>> design) is 0x1bd. The substream ids are 0x80 and 0x81 and imho we
>> should consider those as part of the stream id.
>>
>
> Humm, es_id is a byte so it cannot be 0x1bd ?

Ugh, sorry, I meant 0xbd.
And forgot to mention, the file i'm referring to the file attached
against 1122 on roundup.

-- 
Regards,

Jai



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