[FFmpeg-cvslog] fftools/ffmpeg_enc: factor out setting encoder timebase
Anton Khirnov
git at videolan.org
Wed Aug 30 13:00:11 EEST 2023
ffmpeg | branch: master | Anton Khirnov <anton at khirnov.net> | Fri Jul 21 15:20:21 2023 +0200| [d1a2cd1e139dc87930bd0fd25e9cc30e1545deef] | committer: Anton Khirnov
fftools/ffmpeg_enc: factor out setting encoder timebase
Mainly this fixes handling special values of -enc_time_base ('demux' or
'filter') for audio. It also prints a warning if -enc_time_base is
specified for subtitles, instead of ignoring it silently (current
subtitle encoding API only works with AV_TIME_BASE_Q).
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=d1a2cd1e139dc87930bd0fd25e9cc30e1545deef
---
fftools/ffmpeg_enc.c | 154 +++++++++++++++++++++++++++++++--------------------
1 file changed, 93 insertions(+), 61 deletions(-)
diff --git a/fftools/ffmpeg_enc.c b/fftools/ffmpeg_enc.c
index 3c9fdd3237..c4874b4d78 100644
--- a/fftools/ffmpeg_enc.c
+++ b/fftools/ffmpeg_enc.c
@@ -190,6 +190,93 @@ static int set_encoder_id(OutputFile *of, OutputStream *ost)
return 0;
}
+static int enc_choose_timebase(OutputStream *ost, AVFrame *frame)
+{
+ const OutputFile *of = output_files[ost->file_index];
+ AVCodecContext *enc = ost->enc_ctx;
+ AVRational tb = (AVRational){ 0, 0 };
+ AVRational fr;
+ FrameData *fd;
+
+ if (ost->type == AVMEDIA_TYPE_SUBTITLE) {
+ if (ost->enc_timebase.num)
+ av_log(ost, AV_LOG_WARNING,
+ "-enc_time_base not supported for subtitles, ignoring\n");
+ enc->time_base = AV_TIME_BASE_Q;
+ return 0;
+ }
+
+ fd = frame_data(frame);
+
+ // apply -enc_time_base
+ if (ost->enc_timebase.num == ENC_TIME_BASE_DEMUX &&
+ (fd->dec.tb.num <= 0 || fd->dec.tb.den <= 0)) {
+ av_log(ost, AV_LOG_ERROR,
+ "Demuxing timebase not available - cannot use it for encoding\n");
+ return AVERROR(EINVAL);
+ }
+
+ switch (ost->enc_timebase.num) {
+ case 0: break;
+ case ENC_TIME_BASE_DEMUX: tb = fd->dec.tb; break;
+ case ENC_TIME_BASE_FILTER: tb = frame->time_base; break;
+ default: tb = ost->enc_timebase; break;
+ }
+
+ if (ost->type == AVMEDIA_TYPE_AUDIO) {
+ enc->time_base = tb.num ? tb : (AVRational){ 1, frame->sample_rate };
+ return 0;
+ }
+
+ fr = ost->frame_rate;
+ if (!fr.num)
+ fr = fd->frame_rate_filter;
+ if (!fr.num && !ost->max_frame_rate.num) {
+ fr = (AVRational){25, 1};
+ av_log(ost, AV_LOG_WARNING,
+ "No information "
+ "about the input framerate is available. Falling "
+ "back to a default value of 25fps. Use the -r option "
+ "if you want a different framerate.\n");
+ }
+
+ if (ost->max_frame_rate.num &&
+ (av_q2d(fr) > av_q2d(ost->max_frame_rate) ||
+ !fr.den))
+ fr = ost->max_frame_rate;
+
+ if (enc->codec->supported_framerates && !ost->force_fps) {
+ int idx = av_find_nearest_q_idx(fr, enc->codec->supported_framerates);
+ fr = enc->codec->supported_framerates[idx];
+ }
+ // reduce frame rate for mpeg4 to be within the spec limits
+ if (enc->codec_id == AV_CODEC_ID_MPEG4) {
+ av_reduce(&fr.num, &fr.den,
+ fr.num, fr.den, 65535);
+ }
+
+ if (av_q2d(fr) > 1e3 && ost->vsync_method != VSYNC_PASSTHROUGH &&
+ (ost->vsync_method == VSYNC_CFR || ost->vsync_method == VSYNC_VSCFR ||
+ (ost->vsync_method == VSYNC_AUTO && !(of->format->flags & AVFMT_VARIABLE_FPS)))){
+ av_log(ost, AV_LOG_WARNING, "Frame rate very high for a muxer not efficiently supporting it.\n"
+ "Please consider specifying a lower framerate, a different muxer or "
+ "setting vsync/fps_mode to vfr\n");
+ }
+
+ enc->framerate = fr;
+
+ ost->st->avg_frame_rate = fr;
+
+ if (!(tb.num > 0 && tb.den > 0))
+ tb = av_inv_q(fr);
+ if (!(tb.num > 0 && tb.den > 0))
+ tb = frame->time_base;
+
+ enc->time_base = tb;
+
+ return 0;
+}
+
int enc_open(OutputStream *ost, AVFrame *frame)
{
InputStream *ist = ost->ist;
@@ -221,6 +308,12 @@ int enc_open(OutputStream *ost, AVFrame *frame)
dec_ctx = ist->dec_ctx;
}
+ ret = enc_choose_timebase(ost, frame);
+ if (ret < 0) {
+ av_log(ost, AV_LOG_ERROR, "Could not choose a time base for encoding\n");
+ return AVERROR(EINVAL);
+ }
+
switch (enc_ctx->codec_type) {
case AVMEDIA_TYPE_AUDIO:
enc_ctx->sample_fmt = frame->format;
@@ -234,65 +327,9 @@ int enc_open(OutputStream *ost, AVFrame *frame)
else
enc_ctx->bits_per_raw_sample = FFMIN(fd->bits_per_raw_sample,
av_get_bytes_per_sample(enc_ctx->sample_fmt) << 3);
-
- enc_ctx->time_base = ost->enc_timebase.num > 0 ? ost->enc_timebase :
- av_make_q(1, enc_ctx->sample_rate);
break;
case AVMEDIA_TYPE_VIDEO: {
- AVRational fr = ost->frame_rate;
-
- if (!fr.num)
- fr = fd->frame_rate_filter;
- if (!fr.num && !ost->max_frame_rate.num) {
- fr = (AVRational){25, 1};
- av_log(ost, AV_LOG_WARNING,
- "No information "
- "about the input framerate is available. Falling "
- "back to a default value of 25fps. Use the -r option "
- "if you want a different framerate.\n");
- }
-
- if (ost->max_frame_rate.num &&
- (av_q2d(fr) > av_q2d(ost->max_frame_rate) ||
- !fr.den))
- fr = ost->max_frame_rate;
-
- if (enc->supported_framerates && !ost->force_fps) {
- int idx = av_find_nearest_q_idx(fr, enc->supported_framerates);
- fr = enc->supported_framerates[idx];
- }
- // reduce frame rate for mpeg4 to be within the spec limits
- if (enc_ctx->codec_id == AV_CODEC_ID_MPEG4) {
- av_reduce(&fr.num, &fr.den,
- fr.num, fr.den, 65535);
- }
-
- if (ost->enc_timebase.num == ENC_TIME_BASE_DEMUX) {
- if (fd->dec.tb.num <= 0 || fd->dec.tb.den <= 0) {
- av_log(ost, AV_LOG_ERROR,
- "Demuxing timebase not available - cannot use it for encoding\n");
- return AVERROR(EINVAL);
- }
-
- enc_ctx->time_base = fd->dec.tb;
- } else if (ost->enc_timebase.num == ENC_TIME_BASE_FILTER) {
- enc_ctx->time_base = frame->time_base;
- } else {
- enc_ctx->time_base = ost->enc_timebase.num > 0 ? ost->enc_timebase :
- av_inv_q(fr);
- }
-
- if (!(enc_ctx->time_base.num && enc_ctx->time_base.den))
- enc_ctx->time_base = frame->time_base;
- if ( av_q2d(enc_ctx->time_base) < 0.001 && ost->vsync_method != VSYNC_PASSTHROUGH
- && (ost->vsync_method == VSYNC_CFR || ost->vsync_method == VSYNC_VSCFR ||
- (ost->vsync_method == VSYNC_AUTO && !(of->format->flags & AVFMT_VARIABLE_FPS)))){
- av_log(ost, AV_LOG_WARNING, "Frame rate very high for a muxer not efficiently supporting it.\n"
- "Please consider specifying a lower framerate, a different muxer or "
- "setting vsync/fps_mode to vfr\n");
- }
-
enc_ctx->width = frame->width;
enc_ctx->height = frame->height;
enc_ctx->sample_aspect_ratio = ost->st->sample_aspect_ratio =
@@ -314,10 +351,6 @@ int enc_open(OutputStream *ost, AVFrame *frame)
enc_ctx->colorspace = frame->colorspace;
enc_ctx->chroma_sample_location = frame->chroma_location;
- enc_ctx->framerate = fr;
-
- ost->st->avg_frame_rate = fr;
-
// Field order: autodetection
if (enc_ctx->flags & (AV_CODEC_FLAG_INTERLACED_DCT | AV_CODEC_FLAG_INTERLACED_ME) &&
ost->top_field_first >= 0)
@@ -344,7 +377,6 @@ int enc_open(OutputStream *ost, AVFrame *frame)
break;
}
case AVMEDIA_TYPE_SUBTITLE:
- enc_ctx->time_base = AV_TIME_BASE_Q;
if (!enc_ctx->width) {
enc_ctx->width = ost->ist->par->width;
enc_ctx->height = ost->ist->par->height;
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