Skip to content

Commit

Permalink
AvFormatDecoder: Improve video frame rate selection
Browse files Browse the repository at this point in the history 
- instead of selecting one frame rate, we build a list of possible
values, the most likely/preferred first
- if the first choice is not a standard rate, iterate over the list and
see if there is something better available.
- this picks up errors from streams with some corruption, as well as
picking a better default for streams with a variable frame rate.
- should fix incorrect display mode switching - but further changes
needed to ensure we update the display mode on frame rate changes.
  • Loading branch information
@mark-kendall
mark-kendall committed Jan 15, 2020
1 parent aeb97c5 commit dd96d68
Show file tree
Hide file tree
Showing 2 changed files with 77 additions and 45 deletions.
120 changes: 76 additions & 44 deletions mythtv/libs/libmythtv/decoders/avformatdecoder.cpp
View file
Expand Up @@ -1295,75 +1295,107 @@ int AvFormatDecoder::OpenFile(RingBuffer *rbuffer, bool novideo,
return m_recordingHasPositionMap;
}

float AvFormatDecoder::normalized_fps(AVStream *stream, AVCodecContext *enc)
float AvFormatDecoder::GetVideoFrameRate(AVStream *Stream, AVCodecContext *Context, bool Sanitise)
{
double fps = 0.0;
double avg_fps = 0.0;
double codec_fps = 0.0;
double container_fps = 0.0;
double estimated_fps = 0.0;

if (stream->avg_frame_rate.den && stream->avg_frame_rate.num)
avg_fps = av_q2d(stream->avg_frame_rate); // MKV default_duration
if (Stream->avg_frame_rate.den && Stream->avg_frame_rate.num)
avg_fps = av_q2d(Stream->avg_frame_rate); // MKV default_duration

if (enc->time_base.den && enc->time_base.num) // tbc
codec_fps = 1.0 / av_q2d(enc->time_base) / enc->ticks_per_frame;
if (Context->time_base.den && Context->time_base.num) // tbc
codec_fps = 1.0 / av_q2d(Context->time_base) / Context->ticks_per_frame;
// Some formats report fps waaay too high. (wrong time_base)
if (codec_fps > 121.0 && (enc->time_base.den > 10000) &&
(enc->time_base.num == 1))
if (codec_fps > 121.0 && (Context->time_base.den > 10000) &&
(Context->time_base.num == 1))
{
enc->time_base.num = 1001; // seems pretty standard
if (av_q2d(enc->time_base) > 0)
codec_fps = 1.0 / av_q2d(enc->time_base);
Context->time_base.num = 1001; // seems pretty standard
if (av_q2d(Context->time_base) > 0)
codec_fps = 1.0 / av_q2d(Context->time_base);
}
if (stream->time_base.den && stream->time_base.num) // tbn
container_fps = 1.0 / av_q2d(stream->time_base);
if (stream->r_frame_rate.den && stream->r_frame_rate.num) // tbr
estimated_fps = av_q2d(stream->r_frame_rate);
if (Stream->time_base.den && Stream->time_base.num) // tbn
container_fps = 1.0 / av_q2d(Stream->time_base);
if (Stream->r_frame_rate.den && Stream->r_frame_rate.num) // tbr
estimated_fps = av_q2d(Stream->r_frame_rate);

// build a list of possible rates, best first
vector<double> rates;

// matroska demuxer sets the default_duration to avg_frame_rate
// mov,mp4,m4a,3gp,3g2,mj2 demuxer sets avg_frame_rate
if ((QString(m_ic->iformat->name).contains("matroska") ||
QString(m_ic->iformat->name).contains("mov")) &&
avg_fps < 121.0 && avg_fps > 3.0)
{ // NOLINT(bugprone-branch-clone)
fps = avg_fps;
}
else if (QString(m_ic->iformat->name).contains("avi") &&
container_fps < 121.0 && container_fps > 3.0)
{ // NOLINT(bugprone-branch-clone)
fps = container_fps; // avi uses container fps for timestamps // NOLINT(bugprone-branch-clone)
}
else if (codec_fps < 121.0 && codec_fps > 3.0)
{
fps = codec_fps;
rates.emplace_back(avg_fps);
}
else if (container_fps < 121.0 && container_fps > 3.0)
{
fps = container_fps;
}
else if (avg_fps < 121.0 && avg_fps > 3.0)

if (QString(m_ic->iformat->name).contains("avi") &&
container_fps < 121.0 && container_fps > 3.0)
{
fps = avg_fps;
// avi uses container fps for timestamps
rates.emplace_back(container_fps);
}

if (codec_fps < 121.0 && codec_fps > 3.0)
rates.emplace_back(codec_fps);

if (container_fps < 121.0 && container_fps > 3.0)
rates.emplace_back(container_fps);

if (avg_fps < 121.0 && avg_fps > 3.0)
rates.emplace_back(avg_fps);

// certain H.264 interlaced streams are detected at 2x using estimated (i.e. wrong)
else if (estimated_fps < 121.0 && estimated_fps > 3.0)
if (estimated_fps < 121.0 && estimated_fps > 3.0)
rates.emplace_back(estimated_fps);

// last resort
rates.emplace_back(static_cast<float>(30000.0 / 1001.0));

// debug
if (!qFuzzyCompare(static_cast<float>(rates.front()), m_fps))
{
fps = estimated_fps;
LOG(VB_PLAYBACK, LOG_INFO, LOC +
QString("Selected FPS: %1 (Avg:%2 Mult:%3 Codec:%4 Container:%5 Estimated:%6)")
.arg(static_cast<double>(rates.front())).arg(avg_fps)
.arg(m_fpsMultiplier).arg(codec_fps).arg(container_fps).arg(estimated_fps));
}
else

auto IsStandard = [](double Rate)
{
fps = 30000.0 / 1001.0; // 29.97 fps
}
// List of known, standards based frame rates
static const vector<double> s_normRates =
{
24000.0 / 1001.0, 23.976, 25.0, 30000.0 / 1001.0,
29.97, 30.0, 50.0, 60000.0 / 1001.0, 59.94, 60.0, 100.0,
120000.0 / 1001.0, 119.88, 120.0
};

if (Rate > 1.0 && Rate < 121.0)
for (auto rate : s_normRates)
if (qFuzzyCompare(rate, Rate))
return true;
return false;
};

if (!qFuzzyCompare(static_cast<float>(fps), m_fps))
// If the first choice rate is unusual, see if there is something more 'usual'
if (Sanitise && !IsStandard(rates.front()))
{
LOG(VB_PLAYBACK, LOG_INFO, LOC +
QString("Selected FPS: %1 (Avg:%2 Mult:%3 Codec:%4 Container:%5 Estimated:%6)")
.arg(fps).arg(avg_fps).arg(m_fpsMultiplier).arg(codec_fps).arg(container_fps).arg(estimated_fps));
for (auto rate : rates)
{
if (IsStandard(rate))
{
LOG(VB_GENERAL, LOG_INFO, LOC + QString("%1 is non-standard. Selecting %2 instead.")
.arg(rates.front()).arg(rate));
return static_cast<float>(rate);
}
}
}

return static_cast<float>(fps);
return static_cast<float>(rates.front());
}

#ifdef USING_DXVA2
Expand Down Expand Up @@ -1513,7 +1545,7 @@ void AvFormatDecoder::InitVideoCodec(AVStream *stream, AVCodecContext *enc,

if (selectedStream)
{
m_fps = normalized_fps(stream, enc);
m_fps = GetVideoFrameRate(stream, enc, true);
QSize dim = get_video_dim(*enc);
int width = m_currentWidth = dim.width();
int height = m_currentHeight = dim.height();
Expand Down Expand Up @@ -3131,7 +3163,7 @@ void AvFormatDecoder::MpegPreProcessPkt(AVStream *stream, AVPacket *pkt)
m_reorderedPtsDetected = false;

// fps debugging info
float avFPS = normalized_fps(stream, context);
float avFPS = GetVideoFrameRate(stream, context);
if ((seqFPS > avFPS+0.01F) || (seqFPS < avFPS-0.01F))
{
LOG(VB_PLAYBACK, LOG_INFO, LOC + QString("avFPS(%1) != seqFPS(%2)")
Expand Down Expand Up @@ -3240,7 +3272,7 @@ int AvFormatDecoder::H264PreProcessPkt(AVStream *stream, AVPacket *pkt)
m_reorderedPtsDetected = false;

// fps debugging info
auto avFPS = static_cast<double>(normalized_fps(stream, context));
auto avFPS = static_cast<double>(GetVideoFrameRate(stream, context));
if ((seqFPS > avFPS + 0.01) || (seqFPS < avFPS - 0.01))
{
LOG(VB_PLAYBACK, LOG_INFO, LOC +
Expand Down
2 changes: 1 addition & 1 deletion mythtv/libs/libmythtv/decoders/avformatdecoder.h
View file
Expand Up @@ -246,7 +246,7 @@ class AvFormatDecoder : public DecoderBase

bool GenerateDummyVideoFrames(void);
bool HasVideo(const AVFormatContext *ic);
float normalized_fps(AVStream *stream, AVCodecContext *enc);
float GetVideoFrameRate(AVStream *Stream, AVCodecContext *Context, bool Sanitise = false);
static void av_update_stream_timings_video(AVFormatContext *ic);
static bool OpenAVCodec(AVCodecContext *avctx, const AVCodec *codec);

Expand Down

0 comments on commit dd96d68

Please sign in to comment.