mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
synced 2025-06-04 22:48:54 +00:00
basevideodecoder: reverse playback support
This commit is contained in:
Mark Nauwelaerts
parent
1d99e8eafa
commit
1588ed321c
2 changed files with 304 additions and 82 deletions
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@ -92,6 +92,14 @@
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* approach caters for seeking and duration reporting using estimated input
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* bitrates.
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*
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* Baseclass provides some support for reverse playback, in particular
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* in case incoming data is not packetized or upstream does not provide
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* fragments on keyframe boundaries. However, subclass should then be prepared
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* for the parsing and frame processing stage to occur separately (rather
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* than otherwise the latter immediately following the former),
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* and should ensure the parsing stage properly marks keyframes or rely on
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* upstream to do so properly for incoming data.
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*
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* Things that subclass need to take care of:
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* <itemizedlist>
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* <listitem><para>Provide pad templates</para></listitem>
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@ -162,6 +170,8 @@ static GstVideoFrame *gst_base_video_decoder_new_frame (GstBaseVideoDecoder *
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base_video_decoder);
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static void gst_base_video_decoder_free_frame (GstVideoFrame * frame);
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static void gst_base_video_decoder_clear_queues (GstBaseVideoDecoder * dec);
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GST_BOILERPLATE (GstBaseVideoDecoder, gst_base_video_decoder,
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GstBaseVideoCodec, GST_TYPE_BASE_VIDEO_CODEC);
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@ -216,9 +226,6 @@ gst_base_video_decoder_init (GstBaseVideoDecoder * base_video_decoder,
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gst_base_video_decoder_reset (base_video_decoder, TRUE);
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base_video_decoder->current_frame =
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gst_base_video_decoder_new_frame (base_video_decoder);
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base_video_decoder->sink_clipping = TRUE;
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}
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@ -310,6 +317,7 @@ gst_base_video_decoder_flush (GstBaseVideoDecoder * dec, gboolean hard)
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} else {
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gst_segment_init (&GST_BASE_VIDEO_CODEC (dec)->segment,
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GST_FORMAT_UNDEFINED);
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gst_base_video_decoder_clear_queues (dec);
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}
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/* and get (re)set for the sequel */
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gst_base_video_decoder_reset (dec, FALSE);
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@ -843,6 +851,27 @@ gst_base_video_decoder_get_timestamp_at_offset (GstBaseVideoDecoder *
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GST_TIME_ARGS (offset), GST_TIME_ARGS (*timestamp));
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}
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static void
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gst_base_video_decoder_clear_queues (GstBaseVideoDecoder * dec)
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{
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g_list_foreach (dec->queued, (GFunc) gst_mini_object_unref, NULL);
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g_list_free (dec->queued);
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dec->queued = NULL;
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g_list_foreach (dec->gather, (GFunc) gst_mini_object_unref, NULL);
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g_list_free (dec->gather);
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dec->gather = NULL;
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g_list_foreach (dec->decode, (GFunc) gst_base_video_decoder_free_frame, NULL);
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g_list_free (dec->decode);
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dec->decode = NULL;
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g_list_foreach (dec->parse, (GFunc) gst_mini_object_unref, NULL);
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g_list_free (dec->parse);
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dec->decode = NULL;
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g_list_foreach (dec->parse_gather, (GFunc) gst_base_video_decoder_free_frame,
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NULL);
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g_list_free (dec->parse_gather);
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dec->decode = NULL;
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}
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static void
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gst_base_video_decoder_reset (GstBaseVideoDecoder * base_video_decoder,
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gboolean full)
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@ -857,6 +886,7 @@ gst_base_video_decoder_reset (GstBaseVideoDecoder * base_video_decoder,
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if (full) {
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gst_segment_init (&GST_BASE_VIDEO_CODEC (base_video_decoder)->segment,
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GST_FORMAT_UNDEFINED);
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gst_base_video_decoder_clear_queues (base_video_decoder);
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}
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GST_BASE_VIDEO_CODEC (base_video_decoder)->discont = TRUE;
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@ -890,18 +920,252 @@ gst_base_video_decoder_reset (GstBaseVideoDecoder * base_video_decoder,
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}
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static GstFlowReturn
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gst_base_video_decoder_chain (GstPad * pad, GstBuffer * buf)
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gst_base_video_decoder_chain_forward (GstBaseVideoDecoder * base_video_decoder,
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GstBuffer * buf)
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{
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GstBaseVideoDecoder *base_video_decoder;
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GstBaseVideoDecoderClass *klass;
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GstFlowReturn ret;
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base_video_decoder = GST_BASE_VIDEO_DECODER (gst_pad_get_parent (pad));
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klass = GST_BASE_VIDEO_DECODER_GET_CLASS (base_video_decoder);
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g_return_val_if_fail (base_video_decoder->packetized || klass->parse_data,
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GST_FLOW_ERROR);
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if (base_video_decoder->current_frame == NULL) {
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base_video_decoder->current_frame =
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gst_base_video_decoder_new_frame (base_video_decoder);
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}
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if (GST_BUFFER_TIMESTAMP_IS_VALID (buf)) {
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gst_base_video_decoder_add_timestamp (base_video_decoder, buf);
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}
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base_video_decoder->input_offset += GST_BUFFER_SIZE (buf);
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if (base_video_decoder->packetized) {
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base_video_decoder->current_frame->sink_buffer = buf;
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if (GST_BUFFER_FLAG_IS_SET (buf, GST_BUFFER_FLAG_DELTA_UNIT))
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base_video_decoder->current_frame->is_sync_point = TRUE;
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ret = gst_base_video_decoder_have_frame_2 (base_video_decoder);
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} else {
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gst_adapter_push (base_video_decoder->input_adapter, buf);
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if (!base_video_decoder->have_sync) {
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int n, m;
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GST_DEBUG_OBJECT (base_video_decoder, "no sync, scanning");
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n = gst_adapter_available (base_video_decoder->input_adapter);
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if (klass->capture_mask != 0) {
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m = gst_adapter_masked_scan_uint32 (base_video_decoder->input_adapter,
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klass->capture_mask, klass->capture_pattern, 0, n - 3);
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} else if (klass->scan_for_sync) {
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m = klass->scan_for_sync (base_video_decoder, FALSE, 0, n);
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} else {
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m = 0;
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}
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if (m == -1) {
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GST_ERROR_OBJECT (base_video_decoder, "scan returned no sync");
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gst_adapter_flush (base_video_decoder->input_adapter, n - 3);
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return GST_FLOW_OK;
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} else {
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if (m > 0) {
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if (m >= n) {
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GST_ERROR_OBJECT (base_video_decoder,
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"subclass scanned past end %d >= %d", m, n);
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}
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gst_adapter_flush (base_video_decoder->input_adapter, m);
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if (m < n) {
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GST_DEBUG_OBJECT (base_video_decoder,
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"found possible sync after %d bytes (of %d)", m, n);
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/* this is only "maybe" sync */
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base_video_decoder->have_sync = TRUE;
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}
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}
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}
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}
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do {
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ret = klass->parse_data (base_video_decoder, FALSE);
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} while (ret == GST_FLOW_OK);
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if (ret == GST_BASE_VIDEO_DECODER_FLOW_NEED_DATA) {
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return GST_FLOW_OK;
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}
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}
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return ret;
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}
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static GstFlowReturn
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gst_base_video_decoder_flush_decode (GstBaseVideoDecoder * dec)
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{
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GstFlowReturn res = GST_FLOW_OK;
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GList *walk;
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walk = dec->decode;
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GST_DEBUG_OBJECT (dec, "flushing buffers to decode");
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/* clear buffer and decoder state */
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gst_base_video_decoder_flush (dec, FALSE);
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/* signal have_frame it should not capture frames */
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dec->process = TRUE;
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while (walk) {
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GList *next;
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GstVideoFrame *frame = (GstVideoFrame *) (walk->data);
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GstBuffer *buf = frame->sink_buffer;
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GST_DEBUG_OBJECT (dec, "decoding frame %p, ts %" GST_TIME_FORMAT,
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buf, GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buf)));
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next = g_list_next (walk);
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if (dec->current_frame)
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gst_base_video_decoder_free_frame (dec->current_frame);
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dec->current_frame = frame;
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/* decode buffer, resulting data prepended to queue */
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res = gst_base_video_decoder_have_frame_2 (dec);
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walk = next;
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}
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dec->process = FALSE;
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return res;
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}
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static GstFlowReturn
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gst_base_video_decoder_flush_parse (GstBaseVideoDecoder * dec)
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{
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GstFlowReturn res = GST_FLOW_OK;
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GList *walk;
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walk = dec->parse;
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GST_DEBUG_OBJECT (dec, "flushing buffers to parsing");
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/* clear buffer and decoder state */
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gst_base_video_decoder_flush (dec, FALSE);
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while (walk) {
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GList *next;
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GstBuffer *buf = GST_BUFFER_CAST (walk->data);
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GST_DEBUG_OBJECT (dec, "parsing buffer %p, ts %" GST_TIME_FORMAT,
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buf, GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buf)));
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next = g_list_next (walk);
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/* parse buffer, resulting frames prepended to parse_gather queue */
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gst_buffer_ref (buf);
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res = gst_base_video_decoder_chain_forward (dec, buf);
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/* if we generated output, we can discard the buffer, else we
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* keep it in the queue */
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if (dec->parse_gather) {
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GST_DEBUG_OBJECT (dec, "parsed buffer to %p", dec->parse_gather->data);
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dec->parse = g_list_delete_link (dec->parse, walk);
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gst_buffer_unref (buf);
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} else {
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GST_DEBUG_OBJECT (dec, "buffer did not decode, keeping");
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}
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walk = next;
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}
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/* now we can process frames */
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GST_DEBUG_OBJECT (dec, "checking frames");
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while (dec->parse_gather) {
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GstVideoFrame *frame;
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frame = (GstVideoFrame *) (dec->parse_gather->data);
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/* remove from the gather list */
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dec->parse_gather =
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g_list_delete_link (dec->parse_gather, dec->parse_gather);
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/* copy to decode queue */
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dec->decode = g_list_prepend (dec->decode, frame);
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/* if we copied a keyframe, flush and decode the decode queue */
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if (frame->is_sync_point) {
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GST_DEBUG_OBJECT (dec, "copied keyframe");
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res = gst_base_video_decoder_flush_decode (dec);
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}
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}
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/* now send queued data downstream */
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while (dec->queued) {
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GstBuffer *buf = GST_BUFFER_CAST (dec->queued->data);
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if (G_LIKELY (res == GST_FLOW_OK)) {
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GST_DEBUG_OBJECT (dec, "pushing buffer %p of size %u, "
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"time %" GST_TIME_FORMAT ", dur %" GST_TIME_FORMAT, buf,
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GST_BUFFER_SIZE (buf), GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buf)),
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GST_TIME_ARGS (GST_BUFFER_DURATION (buf)));
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/* should be already, but let's be sure */
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buf = gst_buffer_make_metadata_writable (buf);
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/* avoid stray DISCONT from forward processing,
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* which have no meaning in reverse pushing */
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GST_BUFFER_FLAG_UNSET (buf, GST_BUFFER_FLAG_DISCONT);
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res = gst_pad_push (GST_BASE_VIDEO_CODEC_SRC_PAD (dec), buf);
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} else {
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gst_buffer_unref (buf);
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}
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dec->queued = g_list_delete_link (dec->queued, dec->queued);
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}
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return res;
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}
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static GstFlowReturn
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gst_base_video_decoder_chain_reverse (GstBaseVideoDecoder * dec,
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GstBuffer * buf)
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{
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GstFlowReturn result = GST_FLOW_OK;
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/* if we have a discont, move buffers to the decode list */
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if (!buf || GST_BUFFER_FLAG_IS_SET (buf, GST_BUFFER_FLAG_DISCONT)) {
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GST_DEBUG_OBJECT (dec, "received discont");
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while (dec->gather) {
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GstBuffer *gbuf;
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gbuf = GST_BUFFER_CAST (dec->gather->data);
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/* remove from the gather list */
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dec->gather = g_list_delete_link (dec->gather, dec->gather);
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/* copy to parse queue */
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dec->parse = g_list_prepend (dec->parse, gbuf);
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}
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/* parse and decode stuff in the parse queue */
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gst_base_video_decoder_flush_parse (dec);
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}
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if (G_LIKELY (buf)) {
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GST_DEBUG_OBJECT (dec, "gathering buffer %p of size %u, "
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"time %" GST_TIME_FORMAT ", dur %" GST_TIME_FORMAT, buf,
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GST_BUFFER_SIZE (buf), GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buf)),
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GST_TIME_ARGS (GST_BUFFER_DURATION (buf)));
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/* add buffer to gather queue */
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dec->gather = g_list_prepend (dec->gather, buf);
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}
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return result;
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}
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static GstFlowReturn
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gst_base_video_decoder_chain (GstPad * pad, GstBuffer * buf)
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{
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GstBaseVideoDecoder *base_video_decoder;
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base_video_decoder = GST_BASE_VIDEO_DECODER (GST_PAD_PARENT (pad));
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GST_LOG_OBJECT (base_video_decoder,
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"chain %" GST_TIME_FORMAT " duration %" GST_TIME_FORMAT " size %d",
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GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buf)),
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@ -931,11 +1195,8 @@ gst_base_video_decoder_chain (GstPad * pad, GstBuffer * buf)
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gst_pad_push_event (GST_BASE_VIDEO_CODEC_SRC_PAD (base_video_decoder),
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event);
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if (!ret) {
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#if 0
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/* Other base classes tend to ignore the return value */
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GST_ERROR_OBJECT (base_video_decoder, "new segment event ret=%d", ret);
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return GST_FLOW_ERROR;
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#endif
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}
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}
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@ -961,77 +1222,10 @@ gst_base_video_decoder_chain (GstPad * pad, GstBuffer * buf)
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}
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}
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if (base_video_decoder->current_frame == NULL) {
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base_video_decoder->current_frame =
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gst_base_video_decoder_new_frame (base_video_decoder);
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}
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if (GST_BUFFER_TIMESTAMP_IS_VALID (buf)) {
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gst_base_video_decoder_add_timestamp (base_video_decoder, buf);
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}
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base_video_decoder->input_offset += GST_BUFFER_SIZE (buf);
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if (base_video_decoder->packetized) {
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base_video_decoder->current_frame->sink_buffer = buf;
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ret = gst_base_video_decoder_have_frame_2 (base_video_decoder);
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} else {
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gst_adapter_push (base_video_decoder->input_adapter, buf);
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if (!base_video_decoder->have_sync) {
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int n, m;
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GST_DEBUG_OBJECT (base_video_decoder, "no sync, scanning");
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n = gst_adapter_available (base_video_decoder->input_adapter);
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if (klass->capture_mask != 0) {
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m = gst_adapter_masked_scan_uint32 (base_video_decoder->input_adapter,
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klass->capture_mask, klass->capture_pattern, 0, n - 3);
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} else if (klass->scan_for_sync) {
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m = klass->scan_for_sync (base_video_decoder, FALSE, 0, n);
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} else {
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m = 0;
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}
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if (m == -1) {
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GST_ERROR_OBJECT (base_video_decoder, "scan returned no sync");
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gst_adapter_flush (base_video_decoder->input_adapter, n - 3);
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gst_object_unref (base_video_decoder);
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return GST_FLOW_OK;
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} else {
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if (m > 0) {
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if (m >= n) {
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GST_ERROR_OBJECT (base_video_decoder,
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"subclass scanned past end %d >= %d", m, n);
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}
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gst_adapter_flush (base_video_decoder->input_adapter, m);
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if (m < n) {
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GST_DEBUG_OBJECT (base_video_decoder,
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"found possible sync after %d bytes (of %d)", m, n);
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/* this is only "maybe" sync */
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base_video_decoder->have_sync = TRUE;
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}
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}
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}
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}
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do {
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ret = klass->parse_data (base_video_decoder, FALSE);
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} while (ret == GST_FLOW_OK);
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if (ret == GST_BASE_VIDEO_DECODER_FLOW_NEED_DATA) {
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gst_object_unref (base_video_decoder);
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return GST_FLOW_OK;
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}
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}
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gst_object_unref (base_video_decoder);
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return ret;
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if (GST_BASE_VIDEO_CODEC (base_video_decoder)->segment.rate > 0.0)
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return gst_base_video_decoder_chain_forward (base_video_decoder, buf);
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else
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return gst_base_video_decoder_chain_reverse (base_video_decoder, buf);
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}
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static GstStateChangeReturn
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@ -1288,8 +1482,14 @@ gst_base_video_decoder_finish_frame (GstBaseVideoDecoder * base_video_decoder,
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}
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}
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ret = gst_pad_push (GST_BASE_VIDEO_CODEC_SRC_PAD (base_video_decoder),
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src_buffer);
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if (GST_BASE_VIDEO_CODEC (base_video_decoder)->segment.rate < 0.0) {
|
||||
GST_LOG_OBJECT (base_video_decoder, "queued buffer");
|
||||
base_video_decoder->queued =
|
||||
g_list_prepend (base_video_decoder->queued, src_buffer);
|
||||
} else {
|
||||
ret = gst_pad_push (GST_BASE_VIDEO_CODEC_SRC_PAD (base_video_decoder),
|
||||
src_buffer);
|
||||
}
|
||||
|
||||
done:
|
||||
GST_BASE_VIDEO_CODEC (base_video_decoder)->frames =
|
||||
|
|
@ -1437,6 +1637,14 @@ gst_base_video_decoder_have_frame_2 (GstBaseVideoDecoder * base_video_decoder)
|
|||
g_return_val_if_fail (base_video_decoder_class->handle_frame != NULL,
|
||||
GST_FLOW_ERROR);
|
||||
|
||||
/* capture frames and queue for later processing */
|
||||
if (GST_BASE_VIDEO_CODEC (base_video_decoder)->segment.rate < 0.0 &&
|
||||
!base_video_decoder->process) {
|
||||
base_video_decoder->parse_gather =
|
||||
g_list_prepend (base_video_decoder->parse_gather, frame);
|
||||
goto exit;
|
||||
}
|
||||
|
||||
frame->distance_from_sync = base_video_decoder->distance_from_sync;
|
||||
base_video_decoder->distance_from_sync++;
|
||||
|
||||
|
|
@ -1464,6 +1672,7 @@ gst_base_video_decoder_have_frame_2 (GstBaseVideoDecoder * base_video_decoder)
|
|||
gst_flow_get_name (ret));
|
||||
}
|
||||
|
||||
exit:
|
||||
/* create new frame */
|
||||
base_video_decoder->current_frame =
|
||||
gst_base_video_decoder_new_frame (base_video_decoder);
|
||||
|
|
|
|||
|
|
@ -114,6 +114,19 @@ struct _GstBaseVideoDecoder
|
|||
/* last outgoing ts */
|
||||
GstClockTime last_timestamp;
|
||||
|
||||
/* reverse playback */
|
||||
/* collect input */
|
||||
GList *gather;
|
||||
/* to-be-parsed */
|
||||
GList *parse;
|
||||
/* collected parsed frames */
|
||||
GList *parse_gather;
|
||||
/* frames to be handled == decoded */
|
||||
GList *decode;
|
||||
/* collected output */
|
||||
GList *queued;
|
||||
gboolean process;
|
||||
|
||||
/* no comment ... */
|
||||
guint64 base_picture_number;
|
||||
int reorder_depth;
|
||||
|
|
|
|||
Loading…
Reference in a new issue