[FFmpeg-devel] [PATCH] fftools/ffmpeg_dec: restructure audio/video decoding loop
Anton Khirnov
anton at khirnov.net
Thu May 18 09:36:36 EEST 2023
It currently emulates the long-removed
avcodec_decode_audio4/avcodec_decode_video2 APIs, which obfuscates the
actual decoding flow. Restructure the decoding calls so that they
naturally follow the new avcodec_send_packet()/avcodec_receive_frame()
design.
This is not only significantly easier to read, but also shorter.
---
Now increments error rate for errors from avcodec_send_packet()
---
fftools/ffmpeg_dec.c | 191 +++++++++++++++----------------------------
1 file changed, 65 insertions(+), 126 deletions(-)
diff --git a/fftools/ffmpeg_dec.c b/fftools/ffmpeg_dec.c
index 646b587f9e..ab8c6205c6 100644
--- a/fftools/ffmpeg_dec.c
+++ b/fftools/ffmpeg_dec.c
@@ -31,7 +31,7 @@
#include "ffmpeg.h"
-static void check_decode_result(InputStream *ist, int *got_output, int ret)
+static void check_decode_result(InputStream *ist, int got_output, int ret)
{
if (ret < 0)
ist->decode_errors++;
@@ -39,7 +39,7 @@ static void check_decode_result(InputStream *ist, int *got_output, int ret)
if (ret < 0 && exit_on_error)
exit_program(1);
- if (*got_output && ist->dec_ctx->codec_type != AVMEDIA_TYPE_SUBTITLE) {
+ if (got_output && ist->dec_ctx->codec_type != AVMEDIA_TYPE_SUBTITLE) {
if (ist->decoded_frame->decode_error_flags || (ist->decoded_frame->flags & AV_FRAME_FLAG_CORRUPT)) {
av_log(ist, exit_on_error ? AV_LOG_FATAL : AV_LOG_WARNING,
"corrupt decoded frame\n");
@@ -49,52 +49,6 @@ static void check_decode_result(InputStream *ist, int *got_output, int ret)
}
}
-// This does not quite work like avcodec_decode_audio4/avcodec_decode_video2.
-// There is the following difference: if you got a frame, you must call
-// it again with pkt=NULL. pkt==NULL is treated differently from pkt->size==0
-// (pkt==NULL means get more output, pkt->size==0 is a flush/drain packet)
-static int decode(InputStream *ist, AVCodecContext *avctx,
- AVFrame *frame, int *got_frame, const AVPacket *pkt)
-{
- int ret;
-
- *got_frame = 0;
-
- if (pkt) {
- ret = avcodec_send_packet(avctx, pkt);
- // In particular, we don't expect AVERROR(EAGAIN), because we read all
- // decoded frames with avcodec_receive_frame() until done.
- if (ret < 0 && ret != AVERROR_EOF)
- return ret;
- }
-
- ret = avcodec_receive_frame(avctx, frame);
- if (ret < 0 && ret != AVERROR(EAGAIN))
- return ret;
- if (ret >= 0) {
- if (ist->want_frame_data) {
- FrameData *fd;
-
- av_assert0(!frame->opaque_ref);
- frame->opaque_ref = av_buffer_allocz(sizeof(*fd));
- if (!frame->opaque_ref) {
- av_frame_unref(frame);
- return AVERROR(ENOMEM);
- }
- fd = (FrameData*)frame->opaque_ref->data;
- fd->pts = frame->pts;
- fd->tb = avctx->pkt_timebase;
- fd->idx = avctx->frame_num - 1;
- }
-
- frame->time_base = avctx->pkt_timebase;
-
- *got_frame = 1;
- }
-
- return 0;
-}
-
static int send_frame_to_filters(InputStream *ist, AVFrame *decoded_frame)
{
int i, ret;
@@ -192,25 +146,10 @@ static void audio_ts_process(InputStream *ist, AVFrame *frame)
frame->time_base = tb_filter;
}
-static int decode_audio(InputStream *ist, const AVPacket *pkt, int *got_output,
- int *decode_failed)
+static int decode_audio(InputStream *ist, AVFrame *decoded_frame)
{
- AVFrame *decoded_frame = ist->decoded_frame;
- AVCodecContext *avctx = ist->dec_ctx;
int ret, err = 0;
- update_benchmark(NULL);
- ret = decode(ist, avctx, decoded_frame, got_output, pkt);
- update_benchmark("decode_audio %d.%d", ist->file_index, ist->st->index);
- if (ret < 0)
- *decode_failed = 1;
-
- if (ret != AVERROR_EOF)
- check_decode_result(ist, got_output, ret);
-
- if (!*got_output || ret < 0)
- return ret;
-
ist->samples_decoded += decoded_frame->nb_samples;
ist->frames_decoded++;
@@ -274,24 +213,10 @@ static int64_t video_duration_estimate(const InputStream *ist, const AVFrame *fr
return FFMAX(ist->last_frame_duration_est, 1);
}
-static int decode_video(InputStream *ist, const AVPacket *pkt, int *got_output,
- int eof, int *decode_failed)
+static int decode_video(InputStream *ist, AVFrame *frame)
{
- AVFrame *frame = ist->decoded_frame;
int ret = 0, err = 0;
- // With fate-indeo3-2, we're getting 0-sized packets before EOF for some
- // reason. This seems like a semi-critical bug. Don't trigger EOF, and
- // skip the packet.
- if (!eof && pkt && pkt->size == 0)
- return 0;
-
- update_benchmark(NULL);
- ret = decode(ist, ist->dec_ctx, frame, got_output, pkt);
- update_benchmark("decode_video %d.%d", ist->file_index, ist->st->index);
- if (ret < 0)
- *decode_failed = 1;
-
// The following line may be required in some cases where there is no parser
// or the parser does not has_b_frames correctly
if (ist->par->video_delay < ist->dec_ctx->has_b_frames) {
@@ -307,10 +232,6 @@ static int decode_video(InputStream *ist, const AVPacket *pkt, int *got_output,
ist->par->video_delay);
}
- if (ret != AVERROR_EOF)
- check_decode_result(ist, got_output, ret);
-
- if (*got_output && ret >= 0) {
if (ist->dec_ctx->width != frame->width ||
ist->dec_ctx->height != frame->height ||
ist->dec_ctx->pix_fmt != frame->format) {
@@ -322,10 +243,6 @@ static int decode_video(InputStream *ist, const AVPacket *pkt, int *got_output,
ist->dec_ctx->height,
ist->dec_ctx->pix_fmt);
}
- }
-
- if (!*got_output || ret < 0)
- return ret;
if(ist->top_field_first>=0)
frame->flags |= AV_FRAME_FLAG_TOP_FIELD_FIRST;
@@ -470,7 +387,7 @@ static int transcode_subtitles(InputStream *ist, const AVPacket *pkt)
exit_program(1);
}
- check_decode_result(ist, &got_output, ret);
+ check_decode_result(ist, got_output, ret);
if (ret < 0 || !got_output) {
if (!pkt->size)
@@ -500,40 +417,48 @@ static int send_filter_eof(InputStream *ist)
int dec_packet(InputStream *ist, const AVPacket *pkt, int no_eof)
{
AVCodecContext *dec = ist->dec_ctx;
- AVPacket *avpkt = ist->pkt;
- int ret, repeating = 0;
+ const char *type_desc = av_get_media_type_string(dec->codec_type);
+ int ret;
if (dec->codec_type == AVMEDIA_TYPE_SUBTITLE)
return transcode_subtitles(ist, pkt ? pkt : ist->pkt);
- if (pkt) {
- av_packet_unref(avpkt);
- ret = av_packet_ref(avpkt, pkt);
- if (ret < 0)
- return ret;
+ // With fate-indeo3-2, we're getting 0-sized packets before EOF for some
+ // reason. This seems like a semi-critical bug. Don't trigger EOF, and
+ // skip the packet.
+ if (pkt && pkt->size == 0)
+ return 0;
+
+ ret = avcodec_send_packet(dec, pkt);
+ if (ret < 0 && !(ret == AVERROR_EOF && !pkt)) {
+ // In particular, we don't expect AVERROR(EAGAIN), because we read all
+ // decoded frames with avcodec_receive_frame() until done.
+ av_log(ist, AV_LOG_ERROR, "Error submitting %s to decoder: %s\n",
+ pkt ? "packet" : "EOF", av_err2str(ret));
+ if (exit_on_error)
+ exit_program(1);
+
+ if (ret != AVERROR_EOF)
+ ist->decode_errors++;
+
+ return ret;
}
- // while we have more to decode or while the decoder did output something on EOF
while (1) {
- int got_output = 0;
- int decode_failed = 0;
-
- switch (ist->par->codec_type) {
- case AVMEDIA_TYPE_AUDIO:
- ret = decode_audio (ist, repeating ? NULL : avpkt, &got_output,
- &decode_failed);
- av_packet_unref(avpkt);
- break;
- case AVMEDIA_TYPE_VIDEO:
- ret = decode_video (ist, repeating ? NULL : avpkt, &got_output, !pkt,
- &decode_failed);
+ AVFrame *frame = ist->decoded_frame;
- av_packet_unref(avpkt);
- break;
- default: av_assert0(0);
- }
+ update_benchmark(NULL);
+ ret = avcodec_receive_frame(dec, frame);
+ update_benchmark("decode_%s %d.%d", type_desc,
+ ist->file_index, ist->st->index);
+
+ if (ret != AVERROR_EOF && ret != AVERROR(EAGAIN))
+ check_decode_result(ist, ret >= 0, ret);
- if (ret == AVERROR_EOF) {
+ if (ret == AVERROR(EAGAIN)) {
+ av_assert0(pkt); // should never happen during flushing
+ return 0;
+ } else if (ret == AVERROR_EOF) {
/* after flushing, send an EOF on all the filter inputs attached to the stream */
/* except when looping we need to flush but not to send an EOF */
if (!no_eof) {
@@ -545,25 +470,39 @@ int dec_packet(InputStream *ist, const AVPacket *pkt, int no_eof)
}
return AVERROR_EOF;
+ } else if (ret < 0) {
+ av_log(ist, AV_LOG_ERROR, "Decoding error: %s\n", av_err2str(ret));
+ if (exit_on_error)
+ exit_program(1);
+ return ret;
}
- if (ret < 0) {
- if (decode_failed) {
- av_log(NULL, AV_LOG_ERROR, "Error while decoding stream #%d:%d: %s\n",
- ist->file_index, ist->st->index, av_err2str(ret));
- } else {
- av_log(NULL, AV_LOG_FATAL, "Error while processing the decoded "
- "data for stream #%d:%d\n", ist->file_index, ist->st->index);
+ if (ist->want_frame_data) {
+ FrameData *fd;
+
+ av_assert0(!frame->opaque_ref);
+ frame->opaque_ref = av_buffer_allocz(sizeof(*fd));
+ if (!frame->opaque_ref) {
+ av_frame_unref(frame);
+ report_and_exit(AVERROR(ENOMEM));
}
- if (!decode_failed || exit_on_error)
- exit_program(1);
- return ret;
+ fd = (FrameData*)frame->opaque_ref->data;
+ fd->pts = frame->pts;
+ fd->tb = dec->pkt_timebase;
+ fd->idx = dec->frame_num - 1;
}
- if (!got_output)
- return 0;
+ frame->time_base = dec->pkt_timebase;
+
+ ret = dec->codec_type == AVMEDIA_TYPE_AUDIO ?
+ decode_audio(ist, frame) :
+ decode_video(ist, frame);
- repeating = 1;
+ if (ret < 0) {
+ av_log(NULL, AV_LOG_FATAL, "Error while processing the decoded "
+ "data for stream #%d:%d\n", ist->file_index, ist->st->index);
+ exit_program(1);
+ }
}
}
--
2.39.2
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