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hlsdemux2: Calculate / transfer timing info for preloads

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When fulfilling data requests, transfer timing information so the stream can
calculate data bitrates.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3883>
This commit is contained in:
Jan Schmidt 2022-10-14 23:32:56 +11:00 committed by GStreamer Marge Bot
parent 5192181ef5
commit bdec75f9dc
1 changed files with 143 additions and 34 deletions
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177
subprojects/gst-plugins-good/ext/adaptivedemux2/hls/gsthlsdemux-preloader.c
View file

@ -37,13 +37,19 @@ struct _GstHLSDemuxPreloadRequest
GstHLSDemuxPreloader *preloader; /* Parent preloader */
GstM3U8PreloadHint *hint;
/* Incoming download tracking for the resource */
DownloadRequest *download_request;
gboolean download_is_finished; /* TRUE if the input download request completed / failed */
guint64 download_cur_offset; /* offset of the next expected received data */
guint64 download_content_length; /* Content length (filled in when response headers arrive */
guint64 download_content_length; /* Content length (filled in when response headers arrive) */
GstClockTime request_latency; /* original HTTP request to data latency */
GstClockTime download_first_data_time; /* Arrival timestamp of the first data in the download chunk */
guint64 download_first_data_offset; /* First data byte offset of the download chunk */
/* FIXME: Support multiple target requests? I don't think that can happen in practice,
* since we only download one segment at a time, and MAP requests are distinct from PART requests. */
/* Target tracking for the stream download to deliver data blocks to */
/* Each active preload only needs one target to output to at a time,
* since we only download one segment at a time, and MAP requests are distinct from PART requests,
* so 1 preload = 1 download request by the stream */
guint64 target_cur_offset; /* offset of the next delivered target data */
DownloadRequest *target_request;
};
@ -55,6 +61,9 @@ gst_hls_demux_preload_request_new (GstHLSDemuxPreloader * preloader,
GstHLSDemuxPreloadRequest *req = g_new0 (GstHLSDemuxPreloadRequest, 1);
req->preloader = preloader;
req->hint = gst_m3u8_preload_hint_ref (hint);
req->request_latency = GST_CLOCK_TIME_NONE;
req->download_first_data_time = GST_CLOCK_TIME_NONE;
req->download_first_data_offset = GST_BUFFER_OFFSET_NONE;
return req;
};
@ -167,35 +176,56 @@ gst_hls_demux_preloader_despatch (GstHLSDemuxPreloadRequest * preload_req,
gboolean input_is_finished)
{
GstHLSDemuxPreloader *preloader = preload_req->preloader;
DownloadRequest *download_req = preload_req->download_request;
if (input_is_finished)
preload_req->download_is_finished = TRUE;
else
input_is_finished = preload_req->download_is_finished;
download_request_lock (download_req);
/* Update timestamp tracking */
if (preload_req->request_latency == GST_CLOCK_TIME_NONE) {
if (GST_CLOCK_TIME_IS_VALID (download_req->download_request_time) &&
GST_CLOCK_TIME_IS_VALID (download_req->download_start_time)) {
preload_req->request_latency =
download_req->download_start_time -
download_req->download_request_time;
}
}
if (preload_req->download_first_data_time == GST_CLOCK_TIME_NONE &&
download_request_get_bytes_available (download_req) > 0) {
/* Got the first data of this download burst */
preload_req->download_first_data_time = download_req->download_start_time;
preload_req->download_first_data_offset =
download_request_get_cur_offset (download_req);
}
download_request_unlock (download_req);
/* If there is a target request, see if any of our data should be
* transferred to it, and if it should be despatched as complete */
if (preload_req->target_request != NULL) {
gboolean output_is_finished = input_is_finished;
gboolean despatch_progress = FALSE;
DownloadRequest *target_req = preload_req->target_request;
download_request_lock (preload_req->target_request);
download_request_lock (preload_req->download_request);
download_request_lock (target_req);
download_request_lock (download_req);
DownloadRequestState target_state = preload_req->download_request->state;
DownloadRequestState target_state = download_req->state;
/* Transfer the http status code */
preload_req->target_request->status_code =
preload_req->download_request->status_code;
target_req->status_code = download_req->status_code;
GstBuffer *target_buf =
download_request_take_buffer_range (preload_req->download_request,
GstBuffer *target_buf = download_request_take_buffer_range (download_req,
preload_req->target_cur_offset,
preload_req->target_request->range_end);
target_req->range_end);
if (target_buf != NULL) {
DownloadRequest *req = preload_req->target_request;
/* Deliver data to the target, and update our tracked output position */
preload_req->target_cur_offset =
GST_BUFFER_OFFSET (target_buf) + gst_buffer_get_size (target_buf);
@ -203,50 +233,129 @@ gst_hls_demux_preloader_despatch (GstHLSDemuxPreloadRequest * preload_req,
GST_LOG ("Adding %" G_GSIZE_FORMAT " bytes at offset %" G_GUINT64_FORMAT
" to target download request uri %s range %" G_GINT64_FORMAT " - %"
G_GINT64_FORMAT, gst_buffer_get_size (target_buf),
GST_BUFFER_OFFSET (target_buf), req->uri, req->range_start,
req->range_end);
GST_BUFFER_OFFSET (target_buf), target_req->uri,
target_req->range_start, target_req->range_end);
download_request_add_buffer (req, target_buf);
download_request_add_buffer (target_req, target_buf);
despatch_progress = TRUE; /* Added a buffer, despatch progress callback */
if (req->range_end != -1
&& preload_req->target_cur_offset > req->range_end) {
/* Transfer timing from the input download as best we can, so the receiver can
* calculate bitrates. If all preload requests filled one target download,
* we could just transfer the timestamps, but to handle the case of an
* ongoing chunked connection needs fancier accounting based on the
* arrival times of each data burst */
if (target_req->download_start_time == GST_CLOCK_TIME_NONE) {
if (preload_req->download_first_data_time >
preload_req->request_latency) {
target_req->download_request_time =
preload_req->download_first_data_time -
preload_req->request_latency;
} else {
target_req->download_request_time = 0;
}
target_req->download_start_time = preload_req->download_first_data_time;
target_req->download_newest_data_time =
download_req->download_newest_data_time;
}
if (target_req->range_end != -1
&& preload_req->target_cur_offset > target_req->range_end) {
/* We've delivered all data to satisfy the requested byte range - the target request is complete */
if (target_state == DOWNLOAD_REQUEST_STATE_LOADING) {
target_state = DOWNLOAD_REQUEST_STATE_COMPLETE;
GST_LOG ("target download request uri %s range %" G_GINT64_FORMAT
" - %" G_GINT64_FORMAT " is fully satisfied. Completing",
req->uri, req->range_start, req->range_end);
target_req->uri, target_req->range_start, target_req->range_end);
}
output_is_finished = TRUE;
/* If there's unconsumed data left in the input download, then update
* our variable that tracks the first data arrival time in in a prorata
* fashion (because there's more partial segment data already downloaded
* and we need to preserve a reasonable bitrate estimate. If there's no
* data, but the connection is continuing, then it's returned to a blocking
* read state that'll send more data in the future when
* a new live segment becomes available, so reset our variable as if that
* download was starting again */
guint64 data_avail =
download_request_get_bytes_available (download_req);
if (data_avail > 0) {
/* burst first data offset must have been set by now */
g_assert (preload_req->download_first_data_offset !=
GST_BUFFER_OFFSET_NONE);
/* Calculate how long it took to download the data we have output/discarded
* based on the average bitrate so far.
* time_to_download = total_download_time * consumed_bytes / total_download_bytes */
guint64 new_cur_offset =
download_request_get_cur_offset (download_req);
GstClockTime data_time_offset =
gst_util_uint64_scale (download_req->download_newest_data_time -
preload_req->download_first_data_time,
new_cur_offset - preload_req->download_first_data_offset,
new_cur_offset + data_avail -
preload_req->download_first_data_offset);
preload_req->download_first_data_time += data_time_offset;
preload_req->download_first_data_offset = new_cur_offset;
GST_LOG ("Advancing request timing tracking by %" GST_TIMEP_FORMAT
" to time %" GST_TIMEP_FORMAT " @ offset %" G_GUINT64_FORMAT,
&data_time_offset,
&preload_req->download_first_data_time,
preload_req->download_first_data_offset);
/* Say that this target download finished when the first
* byte of the remaining data arrived */
target_req->download_end_time = preload_req->download_first_data_time;
} else {
/* Reset the download start time */
preload_req->download_first_data_time = GST_CLOCK_TIME_NONE;
preload_req->download_first_data_offset = GST_BUFFER_OFFSET_NONE;
/* Say that this request finished when the most recent data arrived */
target_req->download_end_time =
download_req->download_newest_data_time;
}
}
}
if (input_is_finished
&& target_req->download_end_time == GST_CLOCK_TIME_NONE) {
/* No download end time was set yet - use the input download end time */
target_req->download_end_time = download_req->download_end_time;
}
/* Update the target request's state, which may have been adjusted from the
* input request's state */
preload_req->target_request->state = target_state;
target_req->state = target_state;
/* FIXME: Transfer timing from the input download as best we can, so the receiver can
* calculate bitrates */
if (target_req->headers == NULL && download_req->headers != NULL) {
target_req->headers = gst_structure_copy (download_req->headers);
}
if (target_req->redirect_uri == NULL && download_req->redirect_uri != NULL) {
target_req->redirect_uri = g_strdup (download_req->redirect_uri);
target_req->redirect_permanent = download_req->redirect_permanent;
}
/* We're done with the input download request . */
download_request_unlock (preload_req->download_request);
download_request_unlock (download_req);
if (output_is_finished) {
DownloadRequest *req = preload_req->target_request;
GST_DEBUG ("Finishing target preload request uri: %s, start: %"
G_GINT64_FORMAT " end: %" G_GINT64_FORMAT, req->uri, req->range_start,
req->range_end);
G_GINT64_FORMAT " end: %" G_GINT64_FORMAT, target_req->uri,
target_req->range_start, target_req->range_end);
download_request_despatch_completion (req);
download_request_unlock (req);
download_request_despatch_completion (target_req);
download_request_unlock (target_req);
download_request_unref (req);
download_request_unref (target_req);
preload_req->target_request = NULL;
} else if (despatch_progress) {
DownloadRequest *req = preload_req->target_request;
download_request_despatch_progress (req);
download_request_despatch_progress (target_req);
}
/* Unlock if the target request didn't get released above */
@ -256,8 +365,8 @@ gst_hls_demux_preloader_despatch (GstHLSDemuxPreloadRequest * preload_req,
}
if (input_is_finished) {
if (preload_req->download_request == NULL
|| download_request_get_bytes_available (preload_req->download_request)
if (download_req == NULL
|| download_request_get_bytes_available (download_req)
== 0) {
GstM3U8PreloadHint *hint = preload_req->hint;
GST_DEBUG ("Removing finished+drained preload type %d uri: %s, start: %"