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Small improvement to caching sws scale context and reusing AVFrame objects. About 1.5% less CPU calls, and more even memory allocations (less spikey).

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This commit is contained in:
Jonathan Thomas
2025-06-04 17:18:23 -05:00
parent 9a4dcf252a
commit c95fd837b6
2 changed files with 40 additions and 23 deletions
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58
src/FFmpegReader.cpp
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@@ -74,8 +74,8 @@ FFmpegReader::FFmpegReader(const std::string &path, bool inspect_reader)
seek_audio_frame_found(0), seek_video_frame_found(0),is_duration_known(false), largest_frame_processed(0),
current_video_frame(0), packet(NULL), max_concurrent_frames(OPEN_MP_NUM_PROCESSORS), audio_pts(0),
video_pts(0), pFormatCtx(NULL), videoStream(-1), audioStream(-1), pCodecCtx(NULL), aCodecCtx(NULL),
pStream(NULL), aStream(NULL), pFrame(NULL), previous_packet_location{-1,0},
hold_packet(false) {
pStream(NULL), aStream(NULL), pFrame(NULL), previous_packet_location{-1,0},
hold_packet(false) {
// Initialize FFMpeg, and register all formats and codecs
AV_REGISTER_ALL
@@ -678,6 +678,13 @@ void FFmpegReader::Close() {
}
}
#endif // USE_HW_ACCEL
if (img_convert_ctx) {
sws_freeContext(img_convert_ctx);
img_convert_ctx = nullptr;
}
if (pFrameRGB_cached) {
AV_FREE_FRAME(&pFrameRGB_cached);
}
}
// Close the audio codec
@@ -686,6 +693,11 @@ void FFmpegReader::Close() {
avcodec_flush_buffers(aCodecCtx);
}
AV_FREE_CONTEXT(aCodecCtx);
if (avr_ctx) {
SWR_CLOSE(avr_ctx);
SWR_FREE(&avr_ctx);
avr_ctx = nullptr;
}
}
// Clear final cache
@@ -1469,15 +1481,17 @@ void FFmpegReader::ProcessVideoPacket(int64_t requested_frame) {
int width = info.width;
int64_t video_length = info.video_length;
// Create variables for a RGB Frame (since most videos are not in RGB, we must convert it)
AVFrame *pFrameRGB = nullptr;
// Create or reuse a RGB Frame (since most videos are not in RGB, we must convert it)
AVFrame *pFrameRGB = pFrameRGB_cached;
if (!pFrameRGB) {
pFrameRGB = AV_ALLOCATE_FRAME();
if (pFrameRGB == nullptr)
throw OutOfMemory("Failed to allocate frame buffer", path);
pFrameRGB_cached = pFrameRGB;
}
AV_RESET_FRAME(pFrameRGB);
uint8_t *buffer = nullptr;
// Allocate an AVFrame structure
pFrameRGB = AV_ALLOCATE_FRAME();
if (pFrameRGB == nullptr)
throw OutOfMemory("Failed to allocate frame buffer", path);
// Determine the max size of this source image (based on the timeline's size, the scaling mode,
// and the scaling keyframes). This is a performance improvement, to keep the images as small as possible,
// without losing quality. NOTE: We cannot go smaller than the timeline itself, or the add_layer timeline
@@ -1564,8 +1578,9 @@ void FFmpegReader::ProcessVideoPacket(int64_t requested_frame) {
if (openshot::Settings::Instance()->HIGH_QUALITY_SCALING) {
scale_mode = SWS_BICUBIC;
}
SwsContext *img_convert_ctx = sws_getContext(info.width, info.height, AV_GET_CODEC_PIXEL_FORMAT(pStream, pCodecCtx), width,
height, PIX_FMT_RGBA, scale_mode, NULL, NULL, NULL);
img_convert_ctx = sws_getCachedContext(img_convert_ctx, info.width, info.height, AV_GET_CODEC_PIXEL_FORMAT(pStream, pCodecCtx), width, height, PIX_FMT_RGBA, scale_mode, NULL, NULL, NULL);
if (!img_convert_ctx)
throw OutOfMemory("Failed to initialize sws context", path);
// Resize / Convert to RGB
sws_scale(img_convert_ctx, pFrame->data, pFrame->linesize, 0,
@@ -1590,11 +1605,10 @@ void FFmpegReader::ProcessVideoPacket(int64_t requested_frame) {
last_video_frame = f;
// Free the RGB image
AV_FREE_FRAME(&pFrameRGB);
AV_RESET_FRAME(pFrameRGB);
// Remove frame and packet
RemoveAVFrame(pFrame);
sws_freeContext(img_convert_ctx);
// Remove frame and packet
RemoveAVFrame(pFrame);
// Get video PTS in seconds
video_pts_seconds = (double(video_pts) * info.video_timebase.ToDouble()) + pts_offset_seconds;
@@ -1738,10 +1752,10 @@ void FFmpegReader::ProcessAudioPacket(int64_t requested_frame) {
audio_converted->nb_samples = audio_frame->nb_samples;
av_samples_alloc(audio_converted->data, audio_converted->linesize, info.channels, audio_frame->nb_samples, AV_SAMPLE_FMT_FLTP, 0);
SWRCONTEXT *avr = NULL;
// setup resample context
avr = SWR_ALLOC();
SWRCONTEXT *avr = avr_ctx;
// setup resample context if needed
if (!avr) {
avr = SWR_ALLOC();
#if HAVE_CH_LAYOUT
av_opt_set_chlayout(avr, "in_chlayout", &AV_GET_CODEC_ATTRIBUTES(aStream, aCodecCtx)->ch_layout, 0);
av_opt_set_chlayout(avr, "out_chlayout", &AV_GET_CODEC_ATTRIBUTES(aStream, aCodecCtx)->ch_layout, 0);
@@ -1756,6 +1770,8 @@ void FFmpegReader::ProcessAudioPacket(int64_t requested_frame) {
av_opt_set_int(avr, "in_sample_rate", info.sample_rate, 0);
av_opt_set_int(avr, "out_sample_rate", info.sample_rate, 0);
SWR_INIT(avr);
avr_ctx = avr;
}
// Convert audio samples
int nb_samples = SWR_CONVERT(avr, // audio resample context
@@ -1766,10 +1782,6 @@ void FFmpegReader::ProcessAudioPacket(int64_t requested_frame) {
audio_frame->linesize[0], // input plane size, in bytes (0 if unknown)
audio_frame->nb_samples); // number of input samples to convert
// Deallocate resample buffer
SWR_CLOSE(avr);
SWR_FREE(&avr);
avr = NULL;
int64_t starting_frame_number = -1;
for (int channel_filter = 0; channel_filter < info.channels; channel_filter++) {