[Bf-blender-cvs] [10405b15ecc] master: Cleanup: Refactor seeking code
Richard Antalik
noreply at git.blender.org
Tue Mar 1 23:44:07 CET 2022
Commit: 10405b15ecc3f79e9279ac2eb1f711f4bb1c1cc5
Author: Richard Antalik
Date: Tue Mar 1 23:41:00 2022 +0100
Branches: master
https://developer.blender.org/rB10405b15ecc3f79e9279ac2eb1f711f4bb1c1cc5
Cleanup: Refactor seeking code
Improve readability and reduce indentation levels. No functional changes.
Reviewed By: zeddb
Differential Revision: https://developer.blender.org/D14075
===================================================================
M source/blender/imbuf/intern/anim_movie.c
===================================================================
diff --git a/source/blender/imbuf/intern/anim_movie.c b/source/blender/imbuf/intern/anim_movie.c
index 469141cb996..f97a50ecf47 100644
--- a/source/blender/imbuf/intern/anim_movie.c
+++ b/source/blender/imbuf/intern/anim_movie.c
@@ -867,6 +867,17 @@ static void ffmpeg_decode_store_frame_pts(struct anim *anim)
(int64_t)anim->cur_pts);
}
+static int ffmpeg_read_video_frame(struct anim *anim, AVPacket *packet)
+{
+ int ret = 0;
+ while (ret = av_read_frame(anim->pFormatCtx, packet) >= 0) {
+ if (packet->stream_index == anim->videoStream) {
+ break;
+ }
+ }
+ return ret;
+}
+
/* decode one video frame also considering the packet read into cur_packet */
static int ffmpeg_decode_video_frame(struct anim *anim)
{
@@ -887,7 +898,7 @@ static int ffmpeg_decode_video_frame(struct anim *anim)
anim->cur_packet->stream_index = -1;
}
- while ((rval = av_read_frame(anim->pFormatCtx, anim->cur_packet)) >= 0) {
+ while ((rval = ffmpeg_read_video_frame(anim, anim->cur_packet)) >= 0) {
av_log(anim->pFormatCtx,
AV_LOG_DEBUG,
"%sREAD: strID=%d (VID: %d) dts=%" PRId64 " pts=%" PRId64 " %s\n",
@@ -897,14 +908,13 @@ static int ffmpeg_decode_video_frame(struct anim *anim)
(anim->cur_packet->dts == AV_NOPTS_VALUE) ? -1 : (int64_t)anim->cur_packet->dts,
(anim->cur_packet->pts == AV_NOPTS_VALUE) ? -1 : (int64_t)anim->cur_packet->pts,
(anim->cur_packet->flags & AV_PKT_FLAG_KEY) ? " KEY" : "");
- if (anim->cur_packet->stream_index == anim->videoStream) {
- avcodec_send_packet(anim->pCodecCtx, anim->cur_packet);
- anim->pFrameComplete = avcodec_receive_frame(anim->pCodecCtx, anim->pFrame) == 0;
- if (anim->pFrameComplete) {
- ffmpeg_decode_store_frame_pts(anim);
- break;
- }
+ avcodec_send_packet(anim->pCodecCtx, anim->cur_packet);
+ anim->pFrameComplete = avcodec_receive_frame(anim->pCodecCtx, anim->pFrame) == 0;
+
+ if (anim->pFrameComplete) {
+ ffmpeg_decode_store_frame_pts(anim);
+ break;
}
av_packet_unref(anim->cur_packet);
anim->cur_packet->stream_index = -1;
@@ -1159,13 +1169,59 @@ static int ffmpeg_generic_seek_workaround(struct anim *anim,
return av_seek_frame(anim->pFormatCtx, anim->videoStream, current_pts, AVSEEK_FLAG_BACKWARD);
}
+/* Read packet until timestamp matches `anim->cur_packet`, thus recovering internal `anim` stream
+ * position state. */
+static void ffmpeg_seek_recover_stream_position(struct anim *anim)
+{
+ AVPacket *temp_packet = av_packet_alloc();
+ while (ffmpeg_read_video_frame(anim, temp_packet)) {
+ int64_t current_pts = timestamp_from_pts_or_dts(anim->cur_packet->pts, anim->cur_packet->dts);
+ int64_t temp_pts = timestamp_from_pts_or_dts(temp_packet->pts, temp_packet->dts);
+ av_packet_unref(temp_packet);
+
+ if (current_pts == temp_pts) {
+ break;
+ }
+ }
+ av_packet_free(&temp_packet);
+}
+
+/* Check if seeking and mainly flushing codec buffers is needed. */
+static bool ffmpeg_seek_buffers_need_flushing(struct anim *anim, int position, int64_t seek_pos)
+{
+ /* Get timestamp of packet read after seeking. */
+ AVPacket *temp_packet = av_packet_alloc();
+ ffmpeg_read_video_frame(anim, temp_packet);
+ int64_t gop_pts = timestamp_from_pts_or_dts(temp_packet->pts, temp_packet->dts);
+ av_packet_unref(temp_packet);
+ av_packet_free(&temp_packet);
+
+ /* Seeking gives packet, that is currently read. No seeking was necessary, so buffers don't have
+ * to be flushed. */
+ if (gop_pts == timestamp_from_pts_or_dts(anim->cur_packet->pts, anim->cur_packet->dts)) {
+ return false;
+ }
+
+ /* Packet after seeking is same key frame as current, and further in time. No seeking was
+ * necessary, so buffers don't have to be flushed. But stream position has to be recovered. */
+ if (gop_pts == anim->cur_key_frame_pts && position > anim->cur_position) {
+ ffmpeg_seek_recover_stream_position(anim);
+ return false;
+ }
+
+ /* Seeking was necessary, but we have read packets. Therefore we must seek again. */
+ av_seek_frame(anim->pFormatCtx, anim->videoStream, seek_pos, AVSEEK_FLAG_BACKWARD);
+ anim->cur_key_frame_pts = gop_pts;
+ return true;
+}
+
/* Seek to last necessary key frame. */
static int ffmpeg_seek_to_key_frame(struct anim *anim,
int position,
struct anim_index *tc_index,
int64_t pts_to_search)
{
- int64_t pos;
+ int64_t seek_pos;
int ret;
if (tc_index) {
@@ -1180,23 +1236,23 @@ static int ffmpeg_seek_to_key_frame(struct anim *anim,
uint64_t pts;
uint64_t dts;
- pos = IMB_indexer_get_seek_pos(tc_index, new_frame_index);
+ seek_pos = IMB_indexer_get_seek_pos(tc_index, new_frame_index);
pts = IMB_indexer_get_seek_pos_pts(tc_index, new_frame_index);
dts = IMB_indexer_get_seek_pos_dts(tc_index, new_frame_index);
anim->cur_key_frame_pts = timestamp_from_pts_or_dts(pts, dts);
- av_log(anim->pFormatCtx, AV_LOG_DEBUG, "TC INDEX seek pos = %" PRId64 "\n", pos);
+ av_log(anim->pFormatCtx, AV_LOG_DEBUG, "TC INDEX seek seek_pos = %" PRId64 "\n", seek_pos);
av_log(anim->pFormatCtx, AV_LOG_DEBUG, "TC INDEX seek pts = %" PRIu64 "\n", pts);
av_log(anim->pFormatCtx, AV_LOG_DEBUG, "TC INDEX seek dts = %" PRIu64 "\n", dts);
if (ffmpeg_seek_by_byte(anim->pFormatCtx)) {
- av_log(anim->pFormatCtx, AV_LOG_DEBUG, "... using BYTE pos\n");
+ av_log(anim->pFormatCtx, AV_LOG_DEBUG, "... using BYTE seek_pos\n");
- ret = av_seek_frame(anim->pFormatCtx, -1, pos, AVSEEK_FLAG_BYTE);
+ ret = av_seek_frame(anim->pFormatCtx, -1, seek_pos, AVSEEK_FLAG_BYTE);
}
else {
- av_log(anim->pFormatCtx, AV_LOG_DEBUG, "... using PTS pos\n");
+ av_log(anim->pFormatCtx, AV_LOG_DEBUG, "... using PTS seek_pos\n");
ret = av_seek_frame(
anim->pFormatCtx, anim->videoStream, anim->cur_key_frame_pts, AVSEEK_FLAG_BACKWARD);
}
@@ -1204,58 +1260,25 @@ static int ffmpeg_seek_to_key_frame(struct anim *anim,
else {
/* We have to manually seek with ffmpeg to get to the key frame we want to start decoding from.
*/
- pos = ffmpeg_get_seek_pts(anim, pts_to_search);
- av_log(anim->pFormatCtx, AV_LOG_DEBUG, "NO INDEX final seek pos = %" PRId64 "\n", pos);
+ seek_pos = ffmpeg_get_seek_pts(anim, pts_to_search);
+ av_log(
+ anim->pFormatCtx, AV_LOG_DEBUG, "NO INDEX final seek seek_pos = %" PRId64 "\n", seek_pos);
AVFormatContext *format_ctx = anim->pFormatCtx;
if (format_ctx->iformat->read_seek2 || format_ctx->iformat->read_seek) {
- ret = av_seek_frame(anim->pFormatCtx, anim->videoStream, pos, AVSEEK_FLAG_BACKWARD);
+ ret = av_seek_frame(anim->pFormatCtx, anim->videoStream, seek_pos, AVSEEK_FLAG_BACKWARD);
}
else {
- ret = ffmpeg_generic_seek_workaround(anim, &pos, pts_to_search);
- av_log(anim->pFormatCtx, AV_LOG_DEBUG, "Adjusted final seek pos = %" PRId64 "\n", pos);
+ ret = ffmpeg_generic_seek_workaround(anim, &seek_pos, pts_to_search);
+ av_log(anim->pFormatCtx,
+ AV_LOG_DEBUG,
+ "Adjusted final seek seek_pos = %" PRId64 "\n",
+ seek_pos);
}
- if (ret >= 0) {
- /* Double check if we need to seek and decode all packets. */
- AVPacket *current_gop_start_packet = av_packet_alloc();
- while (av_read_frame(anim->pFormatCtx, current_gop_start_packet) >= 0) {
- if (current_gop_start_packet->stream_index == anim->videoStream) {
- break;
- }
- av_packet_unref(current_gop_start_packet);
- }
- int64_t gop_pts = timestamp_from_pts_or_dts(current_gop_start_packet->pts,
- current_gop_start_packet->dts);
-
- av_packet_free(¤t_gop_start_packet);
- bool same_gop = gop_pts == anim->cur_key_frame_pts;
-
- if (same_gop && position > anim->cur_position) {
- /* Change back to our old frame position so we can simply continue decoding from there. */
- int64_t cur_pts = timestamp_from_pts_or_dts(anim->cur_packet->pts, anim->cur_packet->dts);
-
- if (cur_pts == gop_pts) {
- /* We are already at the correct position. */
- return 0;
- }
- AVPacket *temp = av_packet_alloc();
-
- while (av_read_frame(anim->pFormatCtx, temp) >= 0) {
- int64_t temp_pts = timestamp_from_pts_or_dts(temp->pts, temp->dts);
- if (temp->stream_index == anim->videoStream && temp_pts == cur_pts) {
- break;
- }
- av_packet_unref(temp);
- }
- av_packet_free(&temp);
- return 0;
- }
-
- anim->cur_key_frame_pts = gop_pts;
- /* Seek back so we are at the correct position after we decoded a frame. */
- av_seek_frame(anim->pFormatCtx, anim->videoStream, pos, AVSEEK_FLAG_BACKWARD);
+ if (ret <= 0 && !ffmpeg_seek_buffers_need_flushing(anim, position, seek_pos)) {
+ return 0;
}
}
@@ -1265,7 +1288,7 @@ static int ffmpeg_seek_to_key_frame(struct anim *anim,
"FETCH: "
"error while seeking to DTS = %" PRId64 " (frameno = %d, PTS = %" PRId64
"): errcode = %d\n",
- pos,
+ seek_pos,
position,
pts_to_search,
ret);
@@ -1290,7 +1313,7 @@ static ImBuf *ffmpeg_fetchibuf(struct anim *anim, int position, IMB_Timecode_Typ
return NULL;
}
- av_log(anim->pFormatCtx, AV_LOG_DEBUG, "FETCH: pos=%d\n", position);
+ av_log(anim->pFormatCtx, AV_LOG_DEBUG, "FETCH: seek_pos=%d\n", position);
struct anim_index *tc_index = IMB_anim_open_index(anim, tc);
int64_t pts_to_search = ffmpeg_get_pts_to_search(anim, tc_index, position);
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