[FFmpeg-devel] [PATCH] lavc: deprecate AV_CODEC_FLAG_DROPCHANGED
James Almer
jamrial at gmail.com
Wed Jul 12 15:42:18 EEST 2023
On 7/9/2023 9:57 AM, Anton Khirnov wrote:
> This decoding flag makes decoders drop all frames after a parameter
> change, but what exactly constitutes a parameter change is not well
> defined and will typically depend on the exact use case.
> This functionality then does not belong in libavcodec, but rather in
> user code
> ---
> doc/APIchanges | 3 +++
> libavcodec/avcodec.c | 2 ++
> libavcodec/avcodec.h | 7 ++++---
> libavcodec/decode.c | 11 +++++++++--
> libavcodec/internal.h | 2 ++
> libavcodec/options_table.h | 2 ++
> libavcodec/version_major.h | 1 +
> 7 files changed, 23 insertions(+), 5 deletions(-)
>
> diff --git a/doc/APIchanges b/doc/APIchanges
> index 0cda51fdee..6217502492 100644
> --- a/doc/APIchanges
> +++ b/doc/APIchanges
> @@ -2,6 +2,9 @@ The last version increases of all libraries were on 2023-02-09
>
> API changes, most recent first:
>
> +2023-07-xx - xxxxxxxxxx - lavc 60 - avcodec.h
> + Deprecate AV_CODEC_FLAG_DROPCHANGED without replacement.
> +
> 2023-07-xx - xxxxxxxxxx - lavu 58.15.100 - video_hint.h
> Add AVVideoHint API.
>
> diff --git a/libavcodec/avcodec.c b/libavcodec/avcodec.c
> index 8ccc610227..340abe830e 100644
> --- a/libavcodec/avcodec.c
> +++ b/libavcodec/avcodec.c
> @@ -456,7 +456,9 @@ av_cold int avcodec_close(AVCodecContext *avctx)
>
> av_bsf_free(&avci->bsf);
>
> +#if FF_API_DROPCHANGED
> av_channel_layout_uninit(&avci->initial_ch_layout);
> +#endif
>
> #if CONFIG_LCMS2
> ff_icc_context_uninit(&avci->icc);
> diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
> index d17bdc360d..fe41ecc3c9 100644
> --- a/libavcodec/avcodec.h
> +++ b/libavcodec/avcodec.h
> @@ -226,11 +226,15 @@ typedef struct RcOverride{
> * Use qpel MC.
> */
> #define AV_CODEC_FLAG_QPEL (1 << 4)
> +#if FF_API_DROPCHANGED
> /**
> * Don't output frames whose parameters differ from first
> * decoded frame in stream.
> + *
> + * @deprecated callers should implement this functionality in their own code
> */
> #define AV_CODEC_FLAG_DROPCHANGED (1 << 5)
> +#endif
> /**
> * Request the encoder to output reconstructed frames, i.e.\ frames that would
> * be produced by decoding the encoded bistream. These frames may be retrieved
> @@ -2713,9 +2717,6 @@ int avcodec_send_packet(AVCodecContext *avctx, const AVPacket *avpkt);
> * no more output frames
> * @retval AVERROR(EINVAL) codec not opened, or it is an encoder without the
> * @ref AV_CODEC_FLAG_RECON_FRAME flag enabled
> - * @retval AVERROR_INPUT_CHANGED current decoded frame has changed parameters with
> - * respect to first decoded frame. Applicable when flag
> - * AV_CODEC_FLAG_DROPCHANGED is set.
> * @retval "other negative error code" legitimate decoding errors
> */
> int avcodec_receive_frame(AVCodecContext *avctx, AVFrame *frame);
> diff --git a/libavcodec/decode.c b/libavcodec/decode.c
> index 269633ce10..40eb7679ca 100644
> --- a/libavcodec/decode.c
> +++ b/libavcodec/decode.c
> @@ -740,7 +740,7 @@ fail:
> int ff_decode_receive_frame(AVCodecContext *avctx, AVFrame *frame)
> {
> AVCodecInternal *avci = avctx->internal;
> - int ret, changed;
> + int ret;
>
> if (!avcodec_is_open(avctx) || !av_codec_is_decoder(avctx->codec))
> return AVERROR(EINVAL);
> @@ -770,6 +770,7 @@ FF_DISABLE_DEPRECATION_WARNINGS
> FF_ENABLE_DEPRECATION_WARNINGS
> #endif
>
> +#if FF_API_DROPCHANGED
> if (avctx->flags & AV_CODEC_FLAG_DROPCHANGED) {
>
> if (avctx->frame_num == 1) {
> @@ -790,7 +791,7 @@ FF_ENABLE_DEPRECATION_WARNINGS
> }
>
> if (avctx->frame_num > 1) {
> - changed = avci->initial_format != frame->format;
> + int changed = avci->initial_format != frame->format;
>
> switch(avctx->codec_type) {
> case AVMEDIA_TYPE_VIDEO:
> @@ -815,6 +816,7 @@ FF_ENABLE_DEPRECATION_WARNINGS
> }
> }
> }
> +#endif
> return 0;
> fail:
> av_frame_unref(frame);
> @@ -1739,6 +1741,11 @@ int ff_decode_preinit(AVCodecContext *avctx)
> if (ret < 0)
> return ret;
>
> +#if FF_API_DROPCHANGED
> + if (avctx->flags & AV_CODEC_FLAG_DROPCHANGED)
> + av_log(avctx, AV_LOG_WARNING, "The dropchanged flag is deprecated.\n");
> +#endif
> +
> return 0;
> }
>
> diff --git a/libavcodec/internal.h b/libavcodec/internal.h
> index 868dd46b48..4dce9f6fbb 100644
> --- a/libavcodec/internal.h
> +++ b/libavcodec/internal.h
> @@ -135,12 +135,14 @@ typedef struct AVCodecInternal {
> AVFrame *buffer_frame;
> int draining_done;
>
> +#if FF_API_DROPCHANGED
> /* used when avctx flag AV_CODEC_FLAG_DROPCHANGED is set */
> int changed_frames_dropped;
> int initial_format;
> int initial_width, initial_height;
> int initial_sample_rate;
> AVChannelLayout initial_ch_layout;
> +#endif
>
> #if CONFIG_LCMS2
> FFIccContext icc; /* used to read and write embedded ICC profiles */
> diff --git a/libavcodec/options_table.h b/libavcodec/options_table.h
> index f1a9729c0d..d1244bfc1a 100644
> --- a/libavcodec/options_table.h
> +++ b/libavcodec/options_table.h
> @@ -72,7 +72,9 @@ static const AVOption avcodec_options[] = {
> {"ilme", "interlaced motion estimation", 0, AV_OPT_TYPE_CONST, {.i64 = AV_CODEC_FLAG_INTERLACED_ME }, INT_MIN, INT_MAX, V|E, "flags"},
> {"cgop", "closed GOP", 0, AV_OPT_TYPE_CONST, {.i64 = AV_CODEC_FLAG_CLOSED_GOP }, INT_MIN, INT_MAX, V|E, "flags"},
> {"output_corrupt", "Output even potentially corrupted frames", 0, AV_OPT_TYPE_CONST, {.i64 = AV_CODEC_FLAG_OUTPUT_CORRUPT }, INT_MIN, INT_MAX, V|D, "flags"},
> +#if FF_API_DROPCHANGED
> {"drop_changed", "Drop frames whose parameters differ from first decoded frame", 0, AV_OPT_TYPE_CONST, {.i64 = AV_CODEC_FLAG_DROPCHANGED }, INT_MIN, INT_MAX, A|V|D, "flags"},
Missing the deprecated AVOption flag.
> +#endif
> {"flags2", NULL, OFFSET(flags2), AV_OPT_TYPE_FLAGS, {.i64 = DEFAULT}, 0, UINT_MAX, V|A|E|D|S, "flags2"},
> {"fast", "allow non-spec-compliant speedup tricks", 0, AV_OPT_TYPE_CONST, {.i64 = AV_CODEC_FLAG2_FAST }, INT_MIN, INT_MAX, V|E, "flags2"},
> {"noout", "skip bitstream encoding", 0, AV_OPT_TYPE_CONST, {.i64 = AV_CODEC_FLAG2_NO_OUTPUT }, INT_MIN, INT_MAX, V|E, "flags2"},
> diff --git a/libavcodec/version_major.h b/libavcodec/version_major.h
> index 2f5138d079..95c5aec0c5 100644
> --- a/libavcodec/version_major.h
> +++ b/libavcodec/version_major.h
> @@ -48,6 +48,7 @@
> #define FF_API_SLICE_OFFSET (LIBAVCODEC_VERSION_MAJOR < 61)
> #define FF_API_SUBFRAMES (LIBAVCODEC_VERSION_MAJOR < 61)
> #define FF_API_TICKS_PER_FRAME (LIBAVCODEC_VERSION_MAJOR < 61)
> +#define FF_API_DROPCHANGED (LIBAVCODEC_VERSION_MAJOR < 61)
>
> // reminder to remove CrystalHD decoders on next major bump
> #define FF_CODEC_CRYSTAL_HD (LIBAVCODEC_VERSION_MAJOR < 61)
LGTM, and good idea.
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