[FFmpeg-soc] [soc]: r4279 - seek_api/mpeg.c

[Baptiste Coudurier]

Hi,

On 5/18/2009 10:10 AM, spyfeng wrote:
> Author: spyfeng
> Date: Mon May 18 19:10:33 2009
> New Revision: 4279
> 
> Log:
> Implement new seek api for mpeg.c, just compile passed, need more test.

Please test your code before comitting. Non working code is really
interesting IMHO.

> Modified:
>    seek_api/mpeg.c
> 
> Modified: seek_api/mpeg.c
> ==============================================================================
> --- seek_api/mpeg.c	Sun May 17 15:15:04 2009	(r4278)
> +++ seek_api/mpeg.c	Mon May 18 19:10:33 2009	(r4279)
> @@ -597,6 +597,62 @@ static int64_t mpegps_read_dts(AVFormatC
>      return dts;
>  }
>  
> +static int mpegps_read_seek(struct AVFormatContext *s, int stream_index,
> +                            int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
> +{
> +    AVStream *st = s->streams[stream_index];
> +    int ret, index;
> +    AVPacket pkt1, *pkt = &pkt1;
> +    AVIndexEntry *ie = st->index_entries;
> +    int64_t pos, pts, left_keyframe_ts, left_keyframe_pos;
> +
> +    if (ts <min_ts || ts >max_ts) {
> +        av_log(s, AV_LOG_ERROR, "Wrong range set for target timestamp!\n");
> +        return -1;
> +    }
> +    if (ts < 0 || ts >= s->duration) {
> +        av_log(s, AV_LOG_ERROR, "Timestamp is out of bounds! timestamp=0x%"PRIx64" duration=0x%"PRIx64"\n", ts, s->duration);
> +        return -1;
> +    }

s->duration might not be set reliably.

> +    if (st->discard >= AVDISCARD_ALL) {
> +        av_log(s, AV_LOG_ERROR, "Not active stream!\n");
> +        return -1;
> +    }
> +
> +    index = av_index_search_timestamp(st, ts, flags);
> +    if (index > 0) {
> +        if (ie[index].timestamp >= min_ts && ie[index].timestamp <= max_ts){
> +            url_fseek(s->pb, ie[index].pos, SEEK_SET);
> +            return 0;
> +        }
> +    }
> +
> +    pos = url_ftell(s->pb);
> +    for(;;){
> +        ret = av_read_frame(s, pkt);
> +        if (ret < 0) {
> +            url_fseek(s->pb, pos, SEEK_SET);
> +            return -1;
> +        }
> +
> +        pts = pkt->pts;
> +        av_free_packet(pkt);
> +
> +        if (pkt->flags&PKT_FLAG_KEY) {
> +            if (pts < ts) {
> +                left_keyframe_ts = pts;
> +                left_keyframe_pos = pkt->pos;
> +            }
> +            else
> +                break;
> +        }

This process seems very slow, have a look at av_gen_search in
libavformat/utils.c

[...]

-- 
Baptiste COUDURIER                              GnuPG Key Id: 0x5C1ABAAA
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