mpv/video/decode/vda.c

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video: add vda decode support (with hwaccel) and direct rendering Decoding H264 using Video Decode Acceleration used the custom 'vda_h264_dec' decoder in FFmpeg. The Good: This new implementation has some advantages over the previous one: - It works with Libav: vda_h264_dec never got into Libav since they prefer client applications to use the hwaccel API. - It is way more efficient: in my tests this implementation yields a reduction of CPU usage of roughly ~50% compared to using `vda_h264_dec` and ~65-75% compared to h264 software decoding. This is mainly because `vo_corevideo` was adapted to perform direct rendering of the `CVPixelBufferRefs` created by the Video Decode Acceleration API Framework. The Bad: - `vo_corevideo` is required to use VDA decoding acceleration. - only works with versions of ffmpeg/libav new enough (needs reference refcounting). That is FFmpeg 2.0+ and Libav's git master currently. The Ugly: VDA was hardcoded to use UYVY (2vuy) for the uploaded video texture. One one end this makes the code simple since Apple's OpenGL implementation actually supports this out of the box. It would be nice to support other output image formats and choose the best format depending on the input, or at least making it configurable. My tests indicate that CPU usage actually increases with a 420p IMGFMT output which is not what I would have expected. NOTE: There is a small memory leak with old versions of FFmpeg and with Libav since the CVPixelBufferRef is not automatically released when the AVFrame is deallocated. This can cause leaks inside libavcodec for decoded frames that are discarded before mpv wraps them inside a refcounted mp_image (this only happens on seeks). For frames that enter mpv's refcounting facilities, this is not a problem since we rewrap the CVPixelBufferRef in our mp_image that properly forwards CVPixelBufferRetain/CvPixelBufferRelease calls to the underying CVPixelBufferRef. So, for FFmpeg use something more recent than `b3d63995` for Libav the patch was posted to the dev ML in July and in review since, apparently, the proposed fix is rather hacky.
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/*
* This file is part of mpv.
*
* Copyright (c) 2013 Stefano Pigozzi <stefano.pigozzi@gmail.com>
*
* mpv is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* mpv is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with mpv. If not, see <http://www.gnu.org/licenses/>.
*/
#include <libavcodec/version.h>
#include <libavcodec/vda.h>
#include "common/av_common.h"
#include "common/msg.h"
video: add vda decode support (with hwaccel) and direct rendering Decoding H264 using Video Decode Acceleration used the custom 'vda_h264_dec' decoder in FFmpeg. The Good: This new implementation has some advantages over the previous one: - It works with Libav: vda_h264_dec never got into Libav since they prefer client applications to use the hwaccel API. - It is way more efficient: in my tests this implementation yields a reduction of CPU usage of roughly ~50% compared to using `vda_h264_dec` and ~65-75% compared to h264 software decoding. This is mainly because `vo_corevideo` was adapted to perform direct rendering of the `CVPixelBufferRefs` created by the Video Decode Acceleration API Framework. The Bad: - `vo_corevideo` is required to use VDA decoding acceleration. - only works with versions of ffmpeg/libav new enough (needs reference refcounting). That is FFmpeg 2.0+ and Libav's git master currently. The Ugly: VDA was hardcoded to use UYVY (2vuy) for the uploaded video texture. One one end this makes the code simple since Apple's OpenGL implementation actually supports this out of the box. It would be nice to support other output image formats and choose the best format depending on the input, or at least making it configurable. My tests indicate that CPU usage actually increases with a 420p IMGFMT output which is not what I would have expected. NOTE: There is a small memory leak with old versions of FFmpeg and with Libav since the CVPixelBufferRef is not automatically released when the AVFrame is deallocated. This can cause leaks inside libavcodec for decoded frames that are discarded before mpv wraps them inside a refcounted mp_image (this only happens on seeks). For frames that enter mpv's refcounting facilities, this is not a problem since we rewrap the CVPixelBufferRef in our mp_image that properly forwards CVPixelBufferRetain/CvPixelBufferRelease calls to the underying CVPixelBufferRef. So, for FFmpeg use something more recent than `b3d63995` for Libav the patch was posted to the dev ML in July and in review since, apparently, the proposed fix is rather hacky.
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#include "video/mp_image.h"
#include "video/decode/lavc.h"
#include "config.h"
static int probe(struct vd_lavc_hwdec *hwdec, struct mp_hwdec_info *info,
const char *decoder)
{
hwdec_request_api(info, "vda");
if (mp_codec_to_av_codec_id(decoder) != AV_CODEC_ID_H264)
return HWDEC_ERR_NO_CODEC;
return 0;
}
static int init(struct lavc_ctx *ctx)
{
return 0;
}
video: add vda decode support (with hwaccel) and direct rendering Decoding H264 using Video Decode Acceleration used the custom 'vda_h264_dec' decoder in FFmpeg. The Good: This new implementation has some advantages over the previous one: - It works with Libav: vda_h264_dec never got into Libav since they prefer client applications to use the hwaccel API. - It is way more efficient: in my tests this implementation yields a reduction of CPU usage of roughly ~50% compared to using `vda_h264_dec` and ~65-75% compared to h264 software decoding. This is mainly because `vo_corevideo` was adapted to perform direct rendering of the `CVPixelBufferRefs` created by the Video Decode Acceleration API Framework. The Bad: - `vo_corevideo` is required to use VDA decoding acceleration. - only works with versions of ffmpeg/libav new enough (needs reference refcounting). That is FFmpeg 2.0+ and Libav's git master currently. The Ugly: VDA was hardcoded to use UYVY (2vuy) for the uploaded video texture. One one end this makes the code simple since Apple's OpenGL implementation actually supports this out of the box. It would be nice to support other output image formats and choose the best format depending on the input, or at least making it configurable. My tests indicate that CPU usage actually increases with a 420p IMGFMT output which is not what I would have expected. NOTE: There is a small memory leak with old versions of FFmpeg and with Libav since the CVPixelBufferRef is not automatically released when the AVFrame is deallocated. This can cause leaks inside libavcodec for decoded frames that are discarded before mpv wraps them inside a refcounted mp_image (this only happens on seeks). For frames that enter mpv's refcounting facilities, this is not a problem since we rewrap the CVPixelBufferRef in our mp_image that properly forwards CVPixelBufferRetain/CvPixelBufferRelease calls to the underying CVPixelBufferRef. So, for FFmpeg use something more recent than `b3d63995` for Libav the patch was posted to the dev ML in July and in review since, apparently, the proposed fix is rather hacky.
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struct vda_error {
int code;
char *reason;
};
static const struct vda_error vda_errors[] = {
{ AVERROR(ENOSYS),
"Hardware doesn't support accelerated decoding for this stream" },
{ AVERROR(EINVAL),
video: add vda decode support (with hwaccel) and direct rendering Decoding H264 using Video Decode Acceleration used the custom 'vda_h264_dec' decoder in FFmpeg. The Good: This new implementation has some advantages over the previous one: - It works with Libav: vda_h264_dec never got into Libav since they prefer client applications to use the hwaccel API. - It is way more efficient: in my tests this implementation yields a reduction of CPU usage of roughly ~50% compared to using `vda_h264_dec` and ~65-75% compared to h264 software decoding. This is mainly because `vo_corevideo` was adapted to perform direct rendering of the `CVPixelBufferRefs` created by the Video Decode Acceleration API Framework. The Bad: - `vo_corevideo` is required to use VDA decoding acceleration. - only works with versions of ffmpeg/libav new enough (needs reference refcounting). That is FFmpeg 2.0+ and Libav's git master currently. The Ugly: VDA was hardcoded to use UYVY (2vuy) for the uploaded video texture. One one end this makes the code simple since Apple's OpenGL implementation actually supports this out of the box. It would be nice to support other output image formats and choose the best format depending on the input, or at least making it configurable. My tests indicate that CPU usage actually increases with a 420p IMGFMT output which is not what I would have expected. NOTE: There is a small memory leak with old versions of FFmpeg and with Libav since the CVPixelBufferRef is not automatically released when the AVFrame is deallocated. This can cause leaks inside libavcodec for decoded frames that are discarded before mpv wraps them inside a refcounted mp_image (this only happens on seeks). For frames that enter mpv's refcounting facilities, this is not a problem since we rewrap the CVPixelBufferRef in our mp_image that properly forwards CVPixelBufferRetain/CvPixelBufferRelease calls to the underying CVPixelBufferRef. So, for FFmpeg use something more recent than `b3d63995` for Libav the patch was posted to the dev ML in July and in review since, apparently, the proposed fix is rather hacky.
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"Invalid configuration provided to VDADecoderCreate" },
{ AVERROR_INVALIDDATA,
video: add vda decode support (with hwaccel) and direct rendering Decoding H264 using Video Decode Acceleration used the custom 'vda_h264_dec' decoder in FFmpeg. The Good: This new implementation has some advantages over the previous one: - It works with Libav: vda_h264_dec never got into Libav since they prefer client applications to use the hwaccel API. - It is way more efficient: in my tests this implementation yields a reduction of CPU usage of roughly ~50% compared to using `vda_h264_dec` and ~65-75% compared to h264 software decoding. This is mainly because `vo_corevideo` was adapted to perform direct rendering of the `CVPixelBufferRefs` created by the Video Decode Acceleration API Framework. The Bad: - `vo_corevideo` is required to use VDA decoding acceleration. - only works with versions of ffmpeg/libav new enough (needs reference refcounting). That is FFmpeg 2.0+ and Libav's git master currently. The Ugly: VDA was hardcoded to use UYVY (2vuy) for the uploaded video texture. One one end this makes the code simple since Apple's OpenGL implementation actually supports this out of the box. It would be nice to support other output image formats and choose the best format depending on the input, or at least making it configurable. My tests indicate that CPU usage actually increases with a 420p IMGFMT output which is not what I would have expected. NOTE: There is a small memory leak with old versions of FFmpeg and with Libav since the CVPixelBufferRef is not automatically released when the AVFrame is deallocated. This can cause leaks inside libavcodec for decoded frames that are discarded before mpv wraps them inside a refcounted mp_image (this only happens on seeks). For frames that enter mpv's refcounting facilities, this is not a problem since we rewrap the CVPixelBufferRef in our mp_image that properly forwards CVPixelBufferRetain/CvPixelBufferRelease calls to the underying CVPixelBufferRef. So, for FFmpeg use something more recent than `b3d63995` for Libav the patch was posted to the dev ML in July and in review since, apparently, the proposed fix is rather hacky.
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"Generic error returned by the decoder layer. The cause can range from"
" VDADecoder finding errors in the bitstream to another application"
" using VDA at the moment. Only one application can use VDA at a"
" givent time." },
{ 0, NULL },
};
static void print_vda_error(struct mp_log *log, int lev, char *message,
int error_code)
video: add vda decode support (with hwaccel) and direct rendering Decoding H264 using Video Decode Acceleration used the custom 'vda_h264_dec' decoder in FFmpeg. The Good: This new implementation has some advantages over the previous one: - It works with Libav: vda_h264_dec never got into Libav since they prefer client applications to use the hwaccel API. - It is way more efficient: in my tests this implementation yields a reduction of CPU usage of roughly ~50% compared to using `vda_h264_dec` and ~65-75% compared to h264 software decoding. This is mainly because `vo_corevideo` was adapted to perform direct rendering of the `CVPixelBufferRefs` created by the Video Decode Acceleration API Framework. The Bad: - `vo_corevideo` is required to use VDA decoding acceleration. - only works with versions of ffmpeg/libav new enough (needs reference refcounting). That is FFmpeg 2.0+ and Libav's git master currently. The Ugly: VDA was hardcoded to use UYVY (2vuy) for the uploaded video texture. One one end this makes the code simple since Apple's OpenGL implementation actually supports this out of the box. It would be nice to support other output image formats and choose the best format depending on the input, or at least making it configurable. My tests indicate that CPU usage actually increases with a 420p IMGFMT output which is not what I would have expected. NOTE: There is a small memory leak with old versions of FFmpeg and with Libav since the CVPixelBufferRef is not automatically released when the AVFrame is deallocated. This can cause leaks inside libavcodec for decoded frames that are discarded before mpv wraps them inside a refcounted mp_image (this only happens on seeks). For frames that enter mpv's refcounting facilities, this is not a problem since we rewrap the CVPixelBufferRef in our mp_image that properly forwards CVPixelBufferRetain/CvPixelBufferRelease calls to the underying CVPixelBufferRef. So, for FFmpeg use something more recent than `b3d63995` for Libav the patch was posted to the dev ML in July and in review since, apparently, the proposed fix is rather hacky.
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{
for (int n = 0; vda_errors[n].code < 0; n++)
if (vda_errors[n].code == error_code) {
mp_msg(log, lev, "%s: %s (%d)\n",
message, vda_errors[n].reason, error_code);
video: add vda decode support (with hwaccel) and direct rendering Decoding H264 using Video Decode Acceleration used the custom 'vda_h264_dec' decoder in FFmpeg. The Good: This new implementation has some advantages over the previous one: - It works with Libav: vda_h264_dec never got into Libav since they prefer client applications to use the hwaccel API. - It is way more efficient: in my tests this implementation yields a reduction of CPU usage of roughly ~50% compared to using `vda_h264_dec` and ~65-75% compared to h264 software decoding. This is mainly because `vo_corevideo` was adapted to perform direct rendering of the `CVPixelBufferRefs` created by the Video Decode Acceleration API Framework. The Bad: - `vo_corevideo` is required to use VDA decoding acceleration. - only works with versions of ffmpeg/libav new enough (needs reference refcounting). That is FFmpeg 2.0+ and Libav's git master currently. The Ugly: VDA was hardcoded to use UYVY (2vuy) for the uploaded video texture. One one end this makes the code simple since Apple's OpenGL implementation actually supports this out of the box. It would be nice to support other output image formats and choose the best format depending on the input, or at least making it configurable. My tests indicate that CPU usage actually increases with a 420p IMGFMT output which is not what I would have expected. NOTE: There is a small memory leak with old versions of FFmpeg and with Libav since the CVPixelBufferRef is not automatically released when the AVFrame is deallocated. This can cause leaks inside libavcodec for decoded frames that are discarded before mpv wraps them inside a refcounted mp_image (this only happens on seeks). For frames that enter mpv's refcounting facilities, this is not a problem since we rewrap the CVPixelBufferRef in our mp_image that properly forwards CVPixelBufferRetain/CvPixelBufferRelease calls to the underying CVPixelBufferRef. So, for FFmpeg use something more recent than `b3d63995` for Libav the patch was posted to the dev ML in July and in review since, apparently, the proposed fix is rather hacky.
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return;
}
mp_msg(log, lev, "%s: %d\n", message, error_code);
video: add vda decode support (with hwaccel) and direct rendering Decoding H264 using Video Decode Acceleration used the custom 'vda_h264_dec' decoder in FFmpeg. The Good: This new implementation has some advantages over the previous one: - It works with Libav: vda_h264_dec never got into Libav since they prefer client applications to use the hwaccel API. - It is way more efficient: in my tests this implementation yields a reduction of CPU usage of roughly ~50% compared to using `vda_h264_dec` and ~65-75% compared to h264 software decoding. This is mainly because `vo_corevideo` was adapted to perform direct rendering of the `CVPixelBufferRefs` created by the Video Decode Acceleration API Framework. The Bad: - `vo_corevideo` is required to use VDA decoding acceleration. - only works with versions of ffmpeg/libav new enough (needs reference refcounting). That is FFmpeg 2.0+ and Libav's git master currently. The Ugly: VDA was hardcoded to use UYVY (2vuy) for the uploaded video texture. One one end this makes the code simple since Apple's OpenGL implementation actually supports this out of the box. It would be nice to support other output image formats and choose the best format depending on the input, or at least making it configurable. My tests indicate that CPU usage actually increases with a 420p IMGFMT output which is not what I would have expected. NOTE: There is a small memory leak with old versions of FFmpeg and with Libav since the CVPixelBufferRef is not automatically released when the AVFrame is deallocated. This can cause leaks inside libavcodec for decoded frames that are discarded before mpv wraps them inside a refcounted mp_image (this only happens on seeks). For frames that enter mpv's refcounting facilities, this is not a problem since we rewrap the CVPixelBufferRef in our mp_image that properly forwards CVPixelBufferRetain/CvPixelBufferRelease calls to the underying CVPixelBufferRef. So, for FFmpeg use something more recent than `b3d63995` for Libav the patch was posted to the dev ML in July and in review since, apparently, the proposed fix is rather hacky.
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}
static int init_decoder(struct lavc_ctx *ctx, int fmt, int w, int h)
video: add vda decode support (with hwaccel) and direct rendering Decoding H264 using Video Decode Acceleration used the custom 'vda_h264_dec' decoder in FFmpeg. The Good: This new implementation has some advantages over the previous one: - It works with Libav: vda_h264_dec never got into Libav since they prefer client applications to use the hwaccel API. - It is way more efficient: in my tests this implementation yields a reduction of CPU usage of roughly ~50% compared to using `vda_h264_dec` and ~65-75% compared to h264 software decoding. This is mainly because `vo_corevideo` was adapted to perform direct rendering of the `CVPixelBufferRefs` created by the Video Decode Acceleration API Framework. The Bad: - `vo_corevideo` is required to use VDA decoding acceleration. - only works with versions of ffmpeg/libav new enough (needs reference refcounting). That is FFmpeg 2.0+ and Libav's git master currently. The Ugly: VDA was hardcoded to use UYVY (2vuy) for the uploaded video texture. One one end this makes the code simple since Apple's OpenGL implementation actually supports this out of the box. It would be nice to support other output image formats and choose the best format depending on the input, or at least making it configurable. My tests indicate that CPU usage actually increases with a 420p IMGFMT output which is not what I would have expected. NOTE: There is a small memory leak with old versions of FFmpeg and with Libav since the CVPixelBufferRef is not automatically released when the AVFrame is deallocated. This can cause leaks inside libavcodec for decoded frames that are discarded before mpv wraps them inside a refcounted mp_image (this only happens on seeks). For frames that enter mpv's refcounting facilities, this is not a problem since we rewrap the CVPixelBufferRef in our mp_image that properly forwards CVPixelBufferRetain/CvPixelBufferRelease calls to the underying CVPixelBufferRef. So, for FFmpeg use something more recent than `b3d63995` for Libav the patch was posted to the dev ML in July and in review since, apparently, the proposed fix is rather hacky.
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{
av_vda_default_free(ctx->avctx);
int err = av_vda_default_init(ctx->avctx);
if (err < 0) {
print_vda_error(ctx->log, MSGL_ERR, "failed to init VDA decoder", err);
video: add vda decode support (with hwaccel) and direct rendering Decoding H264 using Video Decode Acceleration used the custom 'vda_h264_dec' decoder in FFmpeg. The Good: This new implementation has some advantages over the previous one: - It works with Libav: vda_h264_dec never got into Libav since they prefer client applications to use the hwaccel API. - It is way more efficient: in my tests this implementation yields a reduction of CPU usage of roughly ~50% compared to using `vda_h264_dec` and ~65-75% compared to h264 software decoding. This is mainly because `vo_corevideo` was adapted to perform direct rendering of the `CVPixelBufferRefs` created by the Video Decode Acceleration API Framework. The Bad: - `vo_corevideo` is required to use VDA decoding acceleration. - only works with versions of ffmpeg/libav new enough (needs reference refcounting). That is FFmpeg 2.0+ and Libav's git master currently. The Ugly: VDA was hardcoded to use UYVY (2vuy) for the uploaded video texture. One one end this makes the code simple since Apple's OpenGL implementation actually supports this out of the box. It would be nice to support other output image formats and choose the best format depending on the input, or at least making it configurable. My tests indicate that CPU usage actually increases with a 420p IMGFMT output which is not what I would have expected. NOTE: There is a small memory leak with old versions of FFmpeg and with Libav since the CVPixelBufferRef is not automatically released when the AVFrame is deallocated. This can cause leaks inside libavcodec for decoded frames that are discarded before mpv wraps them inside a refcounted mp_image (this only happens on seeks). For frames that enter mpv's refcounting facilities, this is not a problem since we rewrap the CVPixelBufferRef in our mp_image that properly forwards CVPixelBufferRetain/CvPixelBufferRelease calls to the underying CVPixelBufferRef. So, for FFmpeg use something more recent than `b3d63995` for Libav the patch was posted to the dev ML in July and in review since, apparently, the proposed fix is rather hacky.
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return -1;
}
return 0;
}
static void uninit(struct lavc_ctx *ctx)
video: add vda decode support (with hwaccel) and direct rendering Decoding H264 using Video Decode Acceleration used the custom 'vda_h264_dec' decoder in FFmpeg. The Good: This new implementation has some advantages over the previous one: - It works with Libav: vda_h264_dec never got into Libav since they prefer client applications to use the hwaccel API. - It is way more efficient: in my tests this implementation yields a reduction of CPU usage of roughly ~50% compared to using `vda_h264_dec` and ~65-75% compared to h264 software decoding. This is mainly because `vo_corevideo` was adapted to perform direct rendering of the `CVPixelBufferRefs` created by the Video Decode Acceleration API Framework. The Bad: - `vo_corevideo` is required to use VDA decoding acceleration. - only works with versions of ffmpeg/libav new enough (needs reference refcounting). That is FFmpeg 2.0+ and Libav's git master currently. The Ugly: VDA was hardcoded to use UYVY (2vuy) for the uploaded video texture. One one end this makes the code simple since Apple's OpenGL implementation actually supports this out of the box. It would be nice to support other output image formats and choose the best format depending on the input, or at least making it configurable. My tests indicate that CPU usage actually increases with a 420p IMGFMT output which is not what I would have expected. NOTE: There is a small memory leak with old versions of FFmpeg and with Libav since the CVPixelBufferRef is not automatically released when the AVFrame is deallocated. This can cause leaks inside libavcodec for decoded frames that are discarded before mpv wraps them inside a refcounted mp_image (this only happens on seeks). For frames that enter mpv's refcounting facilities, this is not a problem since we rewrap the CVPixelBufferRef in our mp_image that properly forwards CVPixelBufferRetain/CvPixelBufferRelease calls to the underying CVPixelBufferRef. So, for FFmpeg use something more recent than `b3d63995` for Libav the patch was posted to the dev ML in July and in review since, apparently, the proposed fix is rather hacky.
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{
if (ctx->avctx)
av_vda_default_free(ctx->avctx);
video: add vda decode support (with hwaccel) and direct rendering Decoding H264 using Video Decode Acceleration used the custom 'vda_h264_dec' decoder in FFmpeg. The Good: This new implementation has some advantages over the previous one: - It works with Libav: vda_h264_dec never got into Libav since they prefer client applications to use the hwaccel API. - It is way more efficient: in my tests this implementation yields a reduction of CPU usage of roughly ~50% compared to using `vda_h264_dec` and ~65-75% compared to h264 software decoding. This is mainly because `vo_corevideo` was adapted to perform direct rendering of the `CVPixelBufferRefs` created by the Video Decode Acceleration API Framework. The Bad: - `vo_corevideo` is required to use VDA decoding acceleration. - only works with versions of ffmpeg/libav new enough (needs reference refcounting). That is FFmpeg 2.0+ and Libav's git master currently. The Ugly: VDA was hardcoded to use UYVY (2vuy) for the uploaded video texture. One one end this makes the code simple since Apple's OpenGL implementation actually supports this out of the box. It would be nice to support other output image formats and choose the best format depending on the input, or at least making it configurable. My tests indicate that CPU usage actually increases with a 420p IMGFMT output which is not what I would have expected. NOTE: There is a small memory leak with old versions of FFmpeg and with Libav since the CVPixelBufferRef is not automatically released when the AVFrame is deallocated. This can cause leaks inside libavcodec for decoded frames that are discarded before mpv wraps them inside a refcounted mp_image (this only happens on seeks). For frames that enter mpv's refcounting facilities, this is not a problem since we rewrap the CVPixelBufferRef in our mp_image that properly forwards CVPixelBufferRetain/CvPixelBufferRelease calls to the underying CVPixelBufferRef. So, for FFmpeg use something more recent than `b3d63995` for Libav the patch was posted to the dev ML in July and in review since, apparently, the proposed fix is rather hacky.
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}
const struct vd_lavc_hwdec mp_vd_lavc_vda = {
.type = HWDEC_VDA,
.image_format = IMGFMT_VDA,
video: add vda decode support (with hwaccel) and direct rendering Decoding H264 using Video Decode Acceleration used the custom 'vda_h264_dec' decoder in FFmpeg. The Good: This new implementation has some advantages over the previous one: - It works with Libav: vda_h264_dec never got into Libav since they prefer client applications to use the hwaccel API. - It is way more efficient: in my tests this implementation yields a reduction of CPU usage of roughly ~50% compared to using `vda_h264_dec` and ~65-75% compared to h264 software decoding. This is mainly because `vo_corevideo` was adapted to perform direct rendering of the `CVPixelBufferRefs` created by the Video Decode Acceleration API Framework. The Bad: - `vo_corevideo` is required to use VDA decoding acceleration. - only works with versions of ffmpeg/libav new enough (needs reference refcounting). That is FFmpeg 2.0+ and Libav's git master currently. The Ugly: VDA was hardcoded to use UYVY (2vuy) for the uploaded video texture. One one end this makes the code simple since Apple's OpenGL implementation actually supports this out of the box. It would be nice to support other output image formats and choose the best format depending on the input, or at least making it configurable. My tests indicate that CPU usage actually increases with a 420p IMGFMT output which is not what I would have expected. NOTE: There is a small memory leak with old versions of FFmpeg and with Libav since the CVPixelBufferRef is not automatically released when the AVFrame is deallocated. This can cause leaks inside libavcodec for decoded frames that are discarded before mpv wraps them inside a refcounted mp_image (this only happens on seeks). For frames that enter mpv's refcounting facilities, this is not a problem since we rewrap the CVPixelBufferRef in our mp_image that properly forwards CVPixelBufferRetain/CvPixelBufferRelease calls to the underying CVPixelBufferRef. So, for FFmpeg use something more recent than `b3d63995` for Libav the patch was posted to the dev ML in July and in review since, apparently, the proposed fix is rather hacky.
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.probe = probe,
.init = init,
.uninit = uninit,
.init_decoder = init_decoder,
video: add vda decode support (with hwaccel) and direct rendering Decoding H264 using Video Decode Acceleration used the custom 'vda_h264_dec' decoder in FFmpeg. The Good: This new implementation has some advantages over the previous one: - It works with Libav: vda_h264_dec never got into Libav since they prefer client applications to use the hwaccel API. - It is way more efficient: in my tests this implementation yields a reduction of CPU usage of roughly ~50% compared to using `vda_h264_dec` and ~65-75% compared to h264 software decoding. This is mainly because `vo_corevideo` was adapted to perform direct rendering of the `CVPixelBufferRefs` created by the Video Decode Acceleration API Framework. The Bad: - `vo_corevideo` is required to use VDA decoding acceleration. - only works with versions of ffmpeg/libav new enough (needs reference refcounting). That is FFmpeg 2.0+ and Libav's git master currently. The Ugly: VDA was hardcoded to use UYVY (2vuy) for the uploaded video texture. One one end this makes the code simple since Apple's OpenGL implementation actually supports this out of the box. It would be nice to support other output image formats and choose the best format depending on the input, or at least making it configurable. My tests indicate that CPU usage actually increases with a 420p IMGFMT output which is not what I would have expected. NOTE: There is a small memory leak with old versions of FFmpeg and with Libav since the CVPixelBufferRef is not automatically released when the AVFrame is deallocated. This can cause leaks inside libavcodec for decoded frames that are discarded before mpv wraps them inside a refcounted mp_image (this only happens on seeks). For frames that enter mpv's refcounting facilities, this is not a problem since we rewrap the CVPixelBufferRef in our mp_image that properly forwards CVPixelBufferRetain/CvPixelBufferRelease calls to the underying CVPixelBufferRef. So, for FFmpeg use something more recent than `b3d63995` for Libav the patch was posted to the dev ML in July and in review since, apparently, the proposed fix is rather hacky.
2013-08-14 13:47:18 +00:00
};