[FFmpeg-devel] [RFC][PATCH] return packets for known codecs earlier when codec probing is done
Baptiste Coudurier
baptiste.coudurier
Mon May 25 22:50:19 CEST 2009
On 5/25/2009 1:10 PM, Baptiste Coudurier wrote:
> On 5/25/2009 7:08 AM, Michael Niedermayer wrote:
>> On Sun, May 24, 2009 at 03:03:33PM -0700, Baptiste Coudurier wrote:
>>> On 5/23/2009 5:58 PM, Baptiste Coudurier wrote:
>>>> On 5/23/2009 5:49 PM, Michael Niedermayer wrote:
>>>>> On Sat, May 23, 2009 at 03:56:11PM -0700, Baptiste Coudurier wrote:
>>>>>> Hi,
>>>>>>
>>>>>> $subject.
>>>>>>
>>>>>> I'd like comments on this. I don't really get why we wouldn't return
>>>>>> packets for known codecs. Why do we buffer them ?
>>>>> if we have packets in the buffer we must return them first, before the
>>>>> current packet even if the codec is known, adding the current packet
>>>>> to the buffer is needed as we return an earlier packet first. And cant
>>>>> return 2 at once.
>>>>> But maybe you meant something else?
>>>> Ok.
>>>>
>>>>>> Problem is that packets for known codecs get buffered but never returned
>>>>>> until codec is sucessfully probed for the unkwnown stream, which might
>>>>>> not even happen.
>>>>> That sounds like a seperat issue,
>>>>> There could be a size limit at which we turn PROBE in NONE and return
>>>>> stuff ...
>>>> Yes, that's what's needed.
>>> What about this ?
>>>
>>> flush_packet_queue needs to flush raw_packet_buffer too.
>>>
>>> Do you have samples that need probing I could test against ?
>> i certainly do but i dont think i would find them, some MPEG files ...
>>
>>
>>> [...]
>>>
>>> int av_read_packet(AVFormatContext *s, AVPacket *pkt)
>>> {
>>> - int ret;
>>> + int ret, i, read_size = 0;
>>> AVStream *st;
>>>
>>> for(;;){
>> i think the read_size variable will in some form have to be put in AVStream
>
> Maybe in the future.
>
>>> @@ -537,10 +537,18 @@ int av_read_packet(AVFormatContext *s, AVPacket *p
>>>
>>> av_init_packet(pkt);
>>> ret= s->iformat->read_packet(s, pkt);
>>> - if (ret < 0)
>>> - return ret;
>>> + if (ret < 0) {
>>> + if (!pktl)
>>> + return ret;
>>> + for (i = 0; i < s->nb_streams; i++)
>>> + if (s->streams[i]->codec->codec_id == CODEC_ID_PROBE)
>>> + s->streams[i]->codec->codec_id = CODEC_ID_NONE;
>>> + continue;
>>> + }
>> i dont like this
>
> What do you propose ? Code needs to return packets buffered when error
> is encoutered. Changed approched.
>
>>> st= s->streams[pkt->stream_index];
>>>
>>> + read_size += pkt->size;
>>> +
>> I think read_size++ is more robust in light of streams of widely
>> varriing bitrate 10mbit video vs. a few kbit speech codec
>
> Ok.
>
>> [...]
>>
>> while(s->raw_packet_buffer){
>> pktl = s->raw_packet_buffer;
>> s->raw_packet_buffer = pktl->next;
>> av_free_packet(&pktl->pkt);
>> av_free(pktl);
>> }
>
> Ok.
>
>
>
> ------------------------------------------------------------------------
>
> Index: libavformat/utils.c
> ===================================================================
> --- libavformat/utils.c (revision 18912)
> +++ libavformat/utils.c (working copy)
> [...]
>
> @@ -537,10 +538,15 @@
>
> av_init_packet(pkt);
> ret= s->iformat->read_packet(s, pkt);
> - if (ret < 0)
> - return ret;
> + if (ret < 0) {
> + if (!pktl)
> + return ret;
> + continue;
> + }
> st= s->streams[pkt->stream_index];
>
> + st->probe_packets++;
> +
This would be better moved under:
@@ -561,6 +566,8 @@
if(st->codec->codec_id == CODEC_ID_PROBE){
AVProbeData *pd = &st->probe_data;
+ st->probe_packets++;
+
pd->buf = av_realloc(pd->buf,
pd->buf_size+pkt->size+AVPROBE_PADDING_SIZE);
--
Baptiste COUDURIER GnuPG Key Id: 0x5C1ABAAA
Key fingerprint 8D77134D20CC9220201FC5DB0AC9325C5C1ABAAA
FFmpeg maintainer http://www.ffmpeg.org
More information about the ffmpeg-devel
mailing list