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Cleanup: Refactor seeking code 

Improve readability and reduce indentation levels. No functional changes.

Reviewed By: zeddb

Differential Revision: https://developer.blender.org/D14075
This commit is contained in:
Richard Antalik 2022-03-01 23:41:00 +01:00
parent 4491c62260
commit 10405b15ec
1 changed files with 83 additions and 60 deletions
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143
source/blender/imbuf/intern/anim_movie.c
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@ -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(&current_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);