Skip to content

Commit

Permalink
Handle seeking within slideshows.
Browse files Browse the repository at this point in the history 
As slideshows only contain a single video frame to be displayed for an arbitary amount of time along with audio, seeking can cause issues as you may jump over the frame to be displayed.

Using an audio DVD of classical music as an example:

1. Each movement contains a single video frame at the beginning.
2. The second movement has just begun and the user skips back several seconds to the end of the first movement.
3. This change detects that a different video frame should be displayed and jumps back further to retrieve the video frame and, once retrieved, returns to the original position to continue playback.

Closes #11579
  • Loading branch information
Richard committed Jun 22, 2013
1 parent 4df1612 commit b670ba5
Show file tree
Hide file tree
Showing 6 changed files with 261 additions and 69 deletions.
4 changes: 2 additions & 2 deletions mythtv/libs/libmythdvdnav/dvdnav/searching.c
View file
Expand Up @@ -696,7 +696,7 @@ dvdnav_status_t dvdnav_relative_time_search(dvdnav_t *this,
for (i = 0; i < 19; i++) {
if (stime[i]/2.0 <= length/2.0) {
offset = dsi->vobu_sri.fwda[i];
if (offset >> 31) {
if (offset != 0x3fffffff) {
new_vobu = cur_vobu + (offset & 0xffff);
} else {
if (cell_nr == last_cell_nr) {
Expand All @@ -715,7 +715,7 @@ dvdnav_status_t dvdnav_relative_time_search(dvdnav_t *this,
if (stime[18 - i]/2.0 >= abs(length)/2.0)
{
offset = dsi->vobu_sri.bwda[i];
if (offset >> 31) {
if (offset != 0x3fffffff) {
new_vobu = cur_vobu - (offset & 0xffff);
} else {
if (cell_nr == first_cell_nr) {
Expand Down
234 changes: 178 additions & 56 deletions mythtv/libs/libmythtv/DVD/avformatdecoderdvd.cpp
View file
Expand Up @@ -7,28 +7,47 @@ extern "C" {
}

#define LOC QString("AFD_DVD: ")
#define INVALID_LBA 0xbfffffff

AvFormatDecoderDVD::AvFormatDecoderDVD(
MythPlayer *parent, const ProgramInfo &pginfo, PlayerFlags flags)
: AvFormatDecoder(parent, pginfo, flags)
, m_curContext(NULL)
, m_lastVideoPkt(NULL)
, m_lbaLastVideoPkt(INVALID_LBA)
, m_framesReq(0)
, m_returnContext(NULL)
{
}

AvFormatDecoderDVD::~AvFormatDecoderDVD()
{
if (m_curContext)
m_curContext->DecrRef();
ReleaseContext(m_curContext);
ReleaseContext(m_returnContext);

while (m_contextList.size() > 0)
m_contextList.takeFirst()->DecrRef();

ReleaseLastVideoPkt();
}

void AvFormatDecoderDVD::ReleaseLastVideoPkt()
{
if (m_lastVideoPkt)
{
av_free_packet(m_lastVideoPkt);
delete m_lastVideoPkt;
m_lastVideoPkt = NULL;
m_lbaLastVideoPkt = INVALID_LBA;
}
}

void AvFormatDecoderDVD::ReleaseContext(MythDVDContext *&context)
{
if (context)
{
context->DecrRef();
context = NULL;
}
}

Expand Down Expand Up @@ -61,46 +80,83 @@ int AvFormatDecoderDVD::ReadPacket(AVFormatContext *ctx, AVPacket* pkt)
if (m_framesReq > 0)
{
m_framesReq--;
av_copy_packet(pkt, m_lastVideoPkt);

if (m_lastVideoPkt->pts != AV_NOPTS_VALUE)
m_lastVideoPkt->pts += pkt->duration;
if (m_lastVideoPkt)
{
av_copy_packet(pkt, m_lastVideoPkt);

if (m_lastVideoPkt->pts != AV_NOPTS_VALUE)
m_lastVideoPkt->pts += pkt->duration;

if (m_lastVideoPkt->dts != AV_NOPTS_VALUE)
m_lastVideoPkt->dts += pkt->duration;
if (m_lastVideoPkt->dts != AV_NOPTS_VALUE)
m_lastVideoPkt->dts += pkt->duration;
}
else
{
LOG(VB_GENERAL, LOG_ERR, LOC + QString( "Need to generate frame @ %1 - %2 but no frame available!")
.arg(pkt->pts)
.arg(m_framesReq));
}
}
else
{
result = av_read_frame(ctx, pkt);
bool gotPacket;

while (result == AVERROR_EOF && errno == EAGAIN)
do
{
if (ringBuffer->DVD()->IsReadingBlocked())
gotPacket = true;

result = av_read_frame(ctx, pkt);

while (result == AVERROR_EOF && errno == EAGAIN)
{
ringBuffer->DVD()->UnblockReading();
result = av_read_frame(ctx, pkt);
if (ringBuffer->DVD()->IsReadingBlocked())
{
if (ringBuffer->DVD()->GetLastEvent() == DVDNAV_HOP_CHANNEL)
{
// Non-seamless jump - clear all buffers
m_framesReq = 0;
ReleaseContext(m_curContext);

while (m_contextList.size() > 0)
m_contextList.takeFirst()->DecrRef();

Reset(true, false, false);
m_audio->Reset();
m_parent->DiscardVideoFrames(false);
}
ringBuffer->DVD()->UnblockReading();
result = av_read_frame(ctx, pkt);
}
else
{
break;
}
}
else

if (result >= 0)
{
break;
}
}
pkt->dts = ringBuffer->DVD()->AdjustTimestamp(pkt->dts);
pkt->pts = ringBuffer->DVD()->AdjustTimestamp(pkt->pts);

if (result >= 0)
{
pkt->dts = ringBuffer->DVD()->AdjustTimestamp(pkt->dts);
pkt->pts = ringBuffer->DVD()->AdjustTimestamp(pkt->pts);
}
if (m_returnContext)
{
// We've jumped in a slideshow and have had to jump again
// to find the right video packet to show so only allow
// the packets through that let us find it.
gotPacket = false;

AVStream *curstream = ic->streams[pkt->stream_index];
if(curstream->codec->codec_type == AVMEDIA_TYPE_DATA)
{
LOG(VB_PLAYBACK, LOG_DEBUG, LOC + QString( "Read DVD context @ %1 - curcontext %2 lastVideo %3 reqFrames %4")
.arg(pkt->pts)
.arg((uint64_t)m_curContext, 0, 16)
.arg((uint64_t)m_lastVideoPkt, 0, 16)
.arg(m_framesReq));
}
AVStream *curstream = ic->streams[pkt->stream_index];

if ((curstream->codec->codec_type == AVMEDIA_TYPE_VIDEO) ||
(curstream->codec->codec_id == AV_CODEC_ID_DVD_NAV))
{
// Allow video or NAV packets through
gotPacket = true;
}
}
}
}while(!gotPacket);
}

return result;
Expand All @@ -110,12 +166,12 @@ void AvFormatDecoderDVD::CheckContext(int64_t pts)
{
if (pts != AV_NOPTS_VALUE)
{
// Remove any contexts we should have
// already processed.(but have somehow jumped past)
while (m_contextList.size() > 0 &&
pts >= m_contextList.first()->GetEndPTS())
{
if (m_curContext)
m_curContext->DecrRef();

ReleaseContext(m_curContext);
m_curContext = m_contextList.takeFirst();

LOG(VB_GENERAL, LOG_ERR, LOC +
Expand All @@ -125,33 +181,58 @@ void AvFormatDecoderDVD::CheckContext(int64_t pts)
.arg(m_curContext->GetEndPTS()));
}

// See whether we can take the next context from the list
if (m_contextList.size() > 0 &&
pts >= m_contextList.first()->GetStartPTS())
{
if (m_curContext)
m_curContext->DecrRef();

ReleaseContext(m_curContext);
m_curContext = m_contextList.takeFirst();

LOG(VB_PLAYBACK, LOG_DEBUG, LOC + QString( "New DVD context @ %1 - %2")
.arg(pts)
.arg(m_curContext->GetNumFramesPresent()));
if (m_curContext->GetLBAPrevVideoFrame() != m_lbaLastVideoPkt)
ReleaseLastVideoPkt();

if (m_curContext->GetNumFramesPresent() == 0)
{
// No video frames present, so we need to generate
// them based on the last 'sequence end' video packet.
m_framesReq = m_curContext->GetNumFrames();
if (m_lastVideoPkt)
{
// No video frames present, so we need to generate
// them based on the last 'sequence end' video packet.
m_framesReq = m_curContext->GetNumFrames();
}
else
{
// There are no video frames in this VOBU and
// we don't have one stored. We've probably
// jumped into the middle of a cell.
// Jump back to the first VOBU that contains
// video so we can get the video frame we need
// before jumping back again.
m_framesReq = 0;
uint32_t lastVideoSector = m_curContext->GetLBAPrevVideoFrame();

if (lastVideoSector != INVALID_LBA)
{
LOG(VB_PLAYBACK, LOG_DEBUG, LOC + QString( "Missing video. Jumping to sector %1")
.arg(lastVideoSector));

ringBuffer->DVD()->SectorSeek(lastVideoSector);

m_returnContext = m_curContext;
m_curContext = NULL;
}
else
{
LOG(VB_GENERAL, LOG_ERR, LOC +
QString("Missing video frame and no previous frame available! lba: %1")
.arg(m_curContext->GetLBA()));
}
}
}
else
{
// Normal VOBU with at least one video frame so we don't need to generate frames.
m_framesReq = 0;
if (m_lastVideoPkt)
{
av_free_packet(m_lastVideoPkt);
delete m_lastVideoPkt;
m_lastVideoPkt = NULL;
}
ReleaseLastVideoPkt();
}
}
}
Expand Down Expand Up @@ -190,18 +271,48 @@ bool AvFormatDecoderDVD::ProcessVideoPacket(AVStream *stream, AVPacket *pkt)

av_init_packet(m_lastVideoPkt);
av_copy_packet(m_lastVideoPkt, pkt);
m_lbaLastVideoPkt = m_curContext->GetLBA();

if (m_returnContext)
{
// After seeking in a slideshow, we needed to find
// the previous video frame to display.
// We've found it now, so we need to jump back to
// where we originally wanted to be.
LOG(VB_PLAYBACK, LOG_DEBUG, LOC + QString( "Found video packet, jumping back to sector %1")
.arg(m_returnContext->GetLBA()));

ringBuffer->DVD()->SectorSeek(m_returnContext->GetLBA());
ReleaseContext(m_returnContext);
}
else
{
if (m_lastVideoPkt->pts != AV_NOPTS_VALUE)
m_lastVideoPkt->pts += pkt->duration;

if (m_lastVideoPkt->dts != AV_NOPTS_VALUE)
m_lastVideoPkt->dts += pkt->duration;

m_framesReq = m_curContext->GetNumFrames() - m_curContext->GetNumFramesPresent();

if (m_lastVideoPkt->pts != AV_NOPTS_VALUE)
m_lastVideoPkt->pts += pkt->duration;
LOG(VB_PLAYBACK, LOG_DEBUG, LOC + QString( "SeqEnd @ %1 - require %2 frame(s)")
.arg(pkt->pts)
.arg(m_framesReq));
}
}

if (m_lastVideoPkt->dts != AV_NOPTS_VALUE)
m_lastVideoPkt->dts += pkt->duration;
return ret;
}

m_framesReq = m_curContext->GetNumFrames() - m_curContext->GetNumFramesPresent();
bool AvFormatDecoderDVD::ProcessVideoFrame(AVStream *stream, AVFrame *mpa_pic)
{
bool ret = true;

LOG(VB_PLAYBACK, LOG_DEBUG, LOC + QString( "SeqEnd @ %1 - require %2 frame(s)")
.arg(pkt->pts)
.arg(m_framesReq));
if (m_returnContext == NULL)
{
// Only process video frames if we're not searching for
// the previous video frame after seeking in a slideshow.
ret = AvFormatDecoder::ProcessVideoFrame(stream, mpa_pic);
}

return ret;
Expand All @@ -224,6 +335,17 @@ bool AvFormatDecoderDVD::ProcessDataPacket(AVStream *curstream, AVPacket *pkt,
// If we don't have a current context, use
// the first in the list
CheckContext(m_contextList.first()->GetStartPTS());

if (m_lastVideoPkt && m_curContext)
{
// If there was no current context but there was
// a video packet, we've almost certainly been
// seeking so set the timestamps of the video
// packet to the new context to ensure we don't
// get sync errors.
m_lastVideoPkt->pts = m_curContext->GetStartPTS();
m_lastVideoPkt->dts = m_lastVideoPkt->pts;
}
}
else
if (m_lastVideoPkt)
Expand Down
5 changes: 5 additions & 0 deletions mythtv/libs/libmythtv/DVD/avformatdecoderdvd.h
View file
Expand Up @@ -19,6 +19,7 @@ class AvFormatDecoderDVD : public AvFormatDecoder
protected:
virtual int ReadPacket(AVFormatContext *ctx, AVPacket *pkt);
virtual bool ProcessVideoPacket(AVStream *stream, AVPacket *pkt);
virtual bool ProcessVideoFrame(AVStream *stream, AVFrame *mpa_pic);
virtual bool ProcessDataPacket(AVStream *curstream, AVPacket *pkt,
DecodeType decodetype);

Expand All @@ -31,13 +32,17 @@ class AvFormatDecoderDVD : public AvFormatDecoder
virtual AudioTrackType GetAudioTrackType(uint stream_index);

void CheckContext(int64_t pts);
void ReleaseLastVideoPkt();
void ReleaseContext(MythDVDContext *&context);

long long DVDFindPosition(long long desiredFrame);

MythDVDContext* m_curContext;
QList<MythDVDContext*> m_contextList;
AVPacket* m_lastVideoPkt;
uint32_t m_lbaLastVideoPkt;
int m_framesReq;
MythDVDContext* m_returnContext;
};

#endif // AVFORMATDECODERDVD_H

0 comments on commit b670ba5

Please sign in to comment.