[FFmpeg-devel,v2] libavformat/dashdec: Avoid multiple HTTP requests for initialization segment that is common among all representations

Hi,

The following patch avoid multiple HTTP requests for initialization segment that is common among all representations.

---
 libavformat/dashdec.c | 82 ++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 71 insertions(+), 11 deletions(-)

> On 10 Apr 2018, at 15:02, sanilraut <raut.sanil@gmail.com> wrote:
> 
> Hi,
> 
> The following patch avoid multiple HTTP requests for initialization segment that is common among all representations.
> 
> ---
> libavformat/dashdec.c | 82 ++++++++++++++++++++++++++++++++++++++++++++-------
> 1 file changed, 71 insertions(+), 11 deletions(-)
> 
> diff --git a/libavformat/dashdec.c b/libavformat/dashdec.c
> index 8bfde4d..6304ad9 100644
> --- a/libavformat/dashdec.c
> +++ b/libavformat/dashdec.c
> @@ -149,6 +149,11 @@ typedef struct DASHContext {
>     char *allowed_extensions;
>     AVDictionary *avio_opts;
>     int max_url_size;
> +
> +    /* Flags for init section*/
> +    int is_init_section_common_video;
> +    int is_init_section_common_audio;
> +
> } DASHContext;
> 
> static int ishttp(char *url)
> @@ -416,9 +421,9 @@ static int open_url(AVFormatContext *s, AVIOContext **pb, const char *url,
>     if (av_strstart(proto_name, "file", NULL)) {
>         if (strcmp(c->allowed_extensions, "ALL") && !av_match_ext(url, c->allowed_extensions)) {
>             av_log(s, AV_LOG_ERROR,
> -                "Filename extension of \'%s\' is not a common multimedia extension, blocked for security reasons.\n"
> -                "If you wish to override this adjust allowed_extensions, you can set it to \'ALL\' to allow all\n",
> -                url);
> +                   "Filename extension of \'%s\' is not a common multimedia extension, blocked for security reasons.\n"
> +                   "If you wish to override this adjust allowed_extensions, you can set it to \'ALL\' to allow all\n",
> +                   url);
>             return AVERROR_INVALIDDATA;
>         }
>     } else if (av_strstart(proto_name, "http", NULL)) {
> @@ -931,7 +936,7 @@ static int parse_manifest_representation(AVFormatContext *s, const char *url,
>                         rep->last_seq_no =(int64_t) strtoll(val, NULL, 10) - 1;
>                         xmlFree(val);
>                     }
> -                 }
> +                }
>             }
> 
>             fragment_timeline_node = find_child_node_by_name(representation_segmenttemplate_node, "SegmentTimeline");
> @@ -1160,7 +1165,7 @@ static int parse_manifest(AVFormatContext *s, const char *url, AVIOContext *in)
>     } else {
>         LIBXML_TEST_VERSION
> 
> -        doc = xmlReadMemory(buffer, filesize, c->base_url, NULL, 0);
> +            doc = xmlReadMemory(buffer, filesize, c->base_url, NULL, 0);
>         root_element = xmlDocGetRootElement(doc);
>         node = root_element;
> 
> @@ -1396,14 +1401,14 @@ static int refresh_manifest(AVFormatContext *s)
> 
>     if (c->n_videos != n_videos) {
>         av_log(c, AV_LOG_ERROR,
> -            "new manifest has mismatched no. of video representations, %d -> %d\n",
> -            n_videos, c->n_videos);
> +               "new manifest has mismatched no. of video representations, %d -> %d\n",
> +               n_videos, c->n_videos);
>         return AVERROR_INVALIDDATA;
>     }
>     if (c->n_audios != n_audios) {
>         av_log(c, AV_LOG_ERROR,
> -            "new manifest has mismatched no. of audio representations, %d -> %d\n",
> -            n_audios, c->n_audios);
> +               "new manifest has mismatched no. of audio representations, %d -> %d\n",
> +               n_audios, c->n_audios);
>         return AVERROR_INVALIDDATA;
>     }
> 
> @@ -1862,6 +1867,45 @@ fail:
>     return ret;
> }
> 
> +static int init_section_compare_video(DASHContext *c)
> +{
> +    int i = 0;
> +    char *url = c->videos[0]->init_section->url;
> +    int64_t url_offset = c->videos[0]->init_section->url_offset;
> +    int64_t size = c->videos[0]->init_section->size;
> +    for (i=0;i<c->n_videos;i++) {
> +        if (av_strcasecmp(c->videos[i]->init_section->url,url) || c->videos[i]->init_section->url_offset != url_offset || c->videos[i]->init_section->size != size) {
> +            return 0;
> +        }
> +    }
> +    return 1;
> +}
> +
> +static int init_section_compare_audio(DASHContext *c)
> +{
> +    int i = 0;
> +    char *url = c->audios[0]->init_section->url;
> +    int64_t url_offset = c->audios[0]->init_section->url_offset;
> +    int64_t size = c->audios[0]->init_section->size;
> +    for (i=0;i<c->n_audios;i++) {
> +        if (av_strcasecmp(c->audios[i]->init_section->url,url) || c->audios[i]->init_section->url_offset != url_offset || c->audios[i]->init_section->size != size) {
> +            return 0;
> +        }
> +    }
> +    return 1;
> +}
> +
> +static void copy_init_section(struct representation *rep_dest, struct representation *rep_src)
> +{
> +    memcpy(rep_dest->init_section, rep_src->init_section, sizeof(rep_src->init_section));
> +    rep_dest->init_sec_buf = av_mallocz(rep_src->init_sec_buf_size);
> +    memcpy(rep_dest->init_sec_buf, rep_src->init_sec_buf, rep_src->init_sec_data_len);
> +    rep_dest->init_sec_buf_size = rep_src->init_sec_buf_size;
> +    rep_dest->init_sec_data_len = rep_src->init_sec_data_len;
> +    rep_dest->cur_timestamp = rep_src->cur_timestamp;
> +}
> +
> +
> static int dash_read_header(AVFormatContext *s)
> {
>     void *u = (s->flags & AVFMT_FLAG_CUSTOM_IO) ? NULL : s->pb;
> @@ -1890,19 +1934,35 @@ static int dash_read_header(AVFormatContext *s)
>         s->duration = (int64_t) c->media_presentation_duration * AV_TIME_BASE;
>     }
> 
> +    if (c->n_videos) {
> +        c->is_init_section_common_video = init_section_compare_video(c);
> +    }
> +
>     /* Open the demuxer for video and audio components if available */
>     for (i = 0; i < c->n_videos; i++) {
>         struct representation *cur_video = c->videos[i];
> +        if (i > 0 && c->is_init_section_common_video) {
> +            copy_init_section(cur_video,c->videos[0]);
> +        }
>         ret = open_demux_for_component(s, cur_video);
> +
>         if (ret)
>             goto fail;
>         cur_video->stream_index = stream_index;
>         ++stream_index;
>     }
> 
> +    if (c->n_audios) {
> +        c->is_init_section_common_audio = init_section_compare_audio(c);
> +    }
> +
>     for (i = 0; i < c->n_audios; i++) {
>         struct representation *cur_audio = c->audios[i];
> +        if (i > 0 && c->is_init_section_common_audio) {
> +            copy_init_section(cur_audio,c->audios[0]);
> +        }
>         ret = open_demux_for_component(s, cur_audio);
> +
>         if (ret)
>             goto fail;
>         cur_audio->stream_index = stream_index;
> @@ -1931,7 +1991,7 @@ static int dash_read_header(AVFormatContext *s)
>                 av_dict_set_int(&pls->assoc_stream->metadata, "variant_bitrate", pls->bandwidth, 0);
>             if (pls->id[0])
>                 av_dict_set(&pls->assoc_stream->metadata, "id", pls->id, 0);
> -         }
> +        }
>         for (i = 0; i < c->n_audios; i++) {
>             struct representation *pls = c->audios[i];
> 
> @@ -2048,7 +2108,7 @@ static int dash_seek(AVFormatContext *s, struct representation *pls, int64_t see
>     int64_t duration = 0;
> 
>     av_log(pls->parent, AV_LOG_VERBOSE, "DASH seek pos[%"PRId64"ms], playlist %d%s\n",
> -            seek_pos_msec, pls->rep_idx, dry_run ? " (dry)" : "");
> +           seek_pos_msec, pls->rep_idx, dry_run ? " (dry)" : "");
> 
>     // single fragment mode
>     if (pls->n_fragments == 1) {
> -- 
> Thanks
> 
> 2.7.4
> 
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Pushed

Thanks
Steven