[FFmpeg-devel] [PATCH] libavformat/dashdec: Avoid multiple HTTP requests for initialization segment that is common among all representations
sanilraut
raut.sanil at gmail.com
Mon Apr 9 10:04:26 EEST 2018
For example:
In the following mpd, initialization segment ( <SegmentTemplate
initialization="test_init.mp4"/> ) is common for all the representations.
As seen in the screen shot (BeforePatch_Sintel_1), there are multiple HTTP
requests for the same initialization segment. After applying the patch,
there is only one request for the initialization segment
(AfterPatch_Sintel_1).
<?xml version="1.0"?>
<!-- MPD file Generated with GPAC version 0.5.2-DEV-revVersion:
0.5.2-426-gc5ad4e4+dfsg5-1build1 at 2017-09-09T18:21:44.557Z-->
<MPD xmlns="urn:mpeg:dash:schema:mpd:2011" minBufferTime="PT1.500S"
type="static" mediaPresentationDuration="PT0H0M52.208S"
maxSegmentDuration="PT0H0M4.000S" profiles="urn:mpeg:dash:profil
e:isoff-live:2011">
<ProgramInformation moreInformationURL="http://gpac.sourceforge.net">
<Title>test.mpd generated by GPAC</Title>
</ProgramInformation>
<Period duration="PT0H0M52.208S">
<AdaptationSet segmentAlignment="true" bitstreamSwitching="true"
maxWidth="1280" maxHeight="720" maxFrameRate="24" par="16:9" lang="und">
<SegmentTemplate initialization="test_init.mp4"/>
<Representation id="1" mimeType="video/mp4" codecs="avc3.4d401f"
width="1280" height="720" frameRate="24" sar="1:1" startWithSAP="1"
bandwidth="2291892">
<SegmentTemplate timescale="96" media="Sintel-1280x720_dash$Number$.m4s"
startNumber="1" duration="384"/>
</Representation>
<Representation id="2" mimeType="video/mp4" codecs="avc3.4d401f"
width="1024" height="576" frameRate="24" sar="1:1" startWithSAP="1"
bandwidth="1635644">
<SegmentTemplate timescale="96" media="Sintel-1024x576_dash$Number$.m4s"
startNumber="1" duration="384"/>
</Representation>
<Representation id="3" mimeType="video/mp4" codecs="avc3.4d401f"
width="768" height="432" frameRate="24" sar="1:1" startWithSAP="1"
bandwidth="1054520">
<SegmentTemplate timescale="96" media="Sintel-768x432_dash$Number$.m4s"
startNumber="1" duration="384"/>
</Representation>
<Representation id="4" mimeType="video/mp4" codecs="avc3.4d401f"
width="640" height="360" frameRate="24" sar="1:1" startWithSAP="1"
bandwidth="662598">
<SegmentTemplate timescale="96" media="Sintel-640x360_dash$Number$.m4s"
startNumber="1" duration="384"/>
</Representation>
<Representation id="5" mimeType="video/mp4" codecs="avc3.4d401f"
width="512" height="288" frameRate="24" sar="1:1" startWithSAP="1"
bandwidth="441780">
<SegmentTemplate timescale="96" media="Sintel-512x288_dash$Number$.m4s"
startNumber="1" duration="384"/>
</Representation>
</AdaptationSet>
</Period>
</MPD>
On Mon, Apr 9, 2018 at 12:02 AM, sanilraut <raut.sanil at gmail.com> wrote:
> Hi,
>
> The following patch avoid multiple HTTP requests for initialization
> segment that is common among all representations.
>
> ---
> libavformat/dashdec.c | 96 ++++++++++++++++++++++++++++++
> ++++++++++++++-------
> 1 file changed, 83 insertions(+), 13 deletions(-)
>
> diff --git a/libavformat/dashdec.c b/libavformat/dashdec.c
> index 8bfde4d..4d0445f 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 +1934,45 @@ static int dash_read_header(AVFormatContext *s)
> s->duration = (int64_t) c->media_presentation_duration *
> AV_TIME_BASE;
> }
>
> + if (c->n_videos != 0) {
> + 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];
> - ret = open_demux_for_component(s, cur_video);
> + if (!c->is_init_section_common_video) {
> + ret = open_demux_for_component(s, cur_video);
> + } else {
> + if (i == 0) {
> + ret = open_demux_for_component(s, cur_video);
> + } else {
> + 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 != 0) {
> + 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];
> - ret = open_demux_for_component(s, cur_audio);
> + if (!c->is_init_section_common_audio) {
> + ret = open_demux_for_component(s, cur_audio);
> + } else {
> + if (i == 0) {
> + ret = open_demux_for_component(s, cur_audio);
> + } else {
> + 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 +2001,7 @@ 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 +2118,7 @@ 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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