[FFmpeg-devel] [PATCH 1/3] avcodec/decode: move processing discard samples to its own function

James Almer jamrial at gmail.com
Sat Jul 8 22:00:36 EEST 2023


Signed-off-by: James Almer <jamrial at gmail.com>
---
 libavcodec/decode.c | 182 +++++++++++++++++++++++---------------------
 1 file changed, 94 insertions(+), 88 deletions(-)

diff --git a/libavcodec/decode.c b/libavcodec/decode.c
index 269633ce10..793ab975f6 100644
--- a/libavcodec/decode.c
+++ b/libavcodec/decode.c
@@ -289,69 +289,14 @@ static int64_t guess_correct_pts(AVCodecContext *ctx,
     return pts;
 }
 
-/*
- * The core of the receive_frame_wrapper for the decoders implementing
- * the simple API. Certain decoders might consume partial packets without
- * returning any output, so this function needs to be called in a loop until it
- * returns EAGAIN.
- **/
-static inline int decode_simple_internal(AVCodecContext *avctx, AVFrame *frame, int64_t *discarded_samples)
+static int discard_samples(AVCodecContext *avctx, AVFrame *frame, int64_t *discarded_samples)
 {
-    AVCodecInternal   *avci = avctx->internal;
-    AVPacket     *const pkt = avci->in_pkt;
-    const FFCodec *const codec = ffcodec(avctx->codec);
-    int got_frame, actual_got_frame;
-    int ret;
-
-    if (!pkt->data && !avci->draining) {
-        av_packet_unref(pkt);
-        ret = ff_decode_get_packet(avctx, pkt);
-        if (ret < 0 && ret != AVERROR_EOF)
-            return ret;
-    }
-
-    // Some codecs (at least wma lossless) will crash when feeding drain packets
-    // after EOF was signaled.
-    if (avci->draining_done)
-        return AVERROR_EOF;
-
-    if (!pkt->data &&
-        !(avctx->codec->capabilities & AV_CODEC_CAP_DELAY ||
-          avctx->active_thread_type & FF_THREAD_FRAME))
-        return AVERROR_EOF;
-
-    got_frame = 0;
-
-    if (HAVE_THREADS && avctx->active_thread_type & FF_THREAD_FRAME) {
-        ret = ff_thread_decode_frame(avctx, frame, &got_frame, pkt);
-    } else {
-        ret = codec->cb.decode(avctx, frame, &got_frame, pkt);
-
-        if (!(codec->caps_internal & FF_CODEC_CAP_SETS_PKT_DTS))
-            frame->pkt_dts = pkt->dts;
-        if (avctx->codec->type == AVMEDIA_TYPE_VIDEO) {
-#if FF_API_FRAME_PKT
-FF_DISABLE_DEPRECATION_WARNINGS
-            if(!avctx->has_b_frames)
-                frame->pkt_pos = pkt->pos;
-FF_ENABLE_DEPRECATION_WARNINGS
-#endif
-            //FIXME these should be under if(!avctx->has_b_frames)
-            /* get_buffer is supposed to set frame parameters */
-            if (!(avctx->codec->capabilities & AV_CODEC_CAP_DR1)) {
-                if (!frame->sample_aspect_ratio.num)  frame->sample_aspect_ratio = avctx->sample_aspect_ratio;
-                if (!frame->width)                    frame->width               = avctx->width;
-                if (!frame->height)                   frame->height              = avctx->height;
-                if (frame->format == AV_PIX_FMT_NONE) frame->format              = avctx->pix_fmt;
-            }
-        }
-    }
-    emms_c();
-    actual_got_frame = got_frame;
+    AVCodecInternal *avci = avctx->internal;
+    int ret = 0;
 
     if (avctx->codec->type == AVMEDIA_TYPE_VIDEO) {
         if (frame->flags & AV_FRAME_FLAG_DISCARD)
-            got_frame = 0;
+            ret = AVERROR(EAGAIN);
     } else if (avctx->codec->type == AVMEDIA_TYPE_AUDIO) {
         uint8_t *side;
         size_t side_size;
@@ -359,16 +304,10 @@ FF_ENABLE_DEPRECATION_WARNINGS
         uint8_t skip_reason = 0;
         uint8_t discard_reason = 0;
 
-        if (ret >= 0 && got_frame) {
             if (frame->format == AV_SAMPLE_FMT_NONE)
                 frame->format = avctx->sample_fmt;
-            if (!frame->ch_layout.nb_channels) {
-                int ret2 = av_channel_layout_copy(&frame->ch_layout, &avctx->ch_layout);
-                if (ret2 < 0) {
-                    ret = ret2;
-                    got_frame = 0;
-                }
-            }
+            if (!frame->ch_layout.nb_channels)
+                ret = av_channel_layout_copy(&frame->ch_layout, &avctx->ch_layout);
 #if FF_API_OLD_CHANNEL_LAYOUT
 FF_DISABLE_DEPRECATION_WARNINGS
             if (!frame->channel_layout)
@@ -380,7 +319,6 @@ FF_ENABLE_DEPRECATION_WARNINGS
 #endif
             if (!frame->sample_rate)
                 frame->sample_rate = avctx->sample_rate;
-        }
 
         side= av_packet_get_side_data(avci->last_pkt_props, AV_PKT_DATA_SKIP_SAMPLES, &side_size);
         if(side && side_size>=10) {
@@ -393,21 +331,21 @@ FF_ENABLE_DEPRECATION_WARNINGS
             discard_reason = AV_RL8(side + 9);
         }
 
-        if ((frame->flags & AV_FRAME_FLAG_DISCARD) && got_frame &&
+        if ((frame->flags & AV_FRAME_FLAG_DISCARD) && !ret &&
             !(avctx->flags2 & AV_CODEC_FLAG2_SKIP_MANUAL)) {
             avci->skip_samples = FFMAX(0, avci->skip_samples - frame->nb_samples);
-            got_frame = 0;
             *discarded_samples += frame->nb_samples;
+            ret = AVERROR(EAGAIN);
         }
 
-        if (avci->skip_samples > 0 && got_frame &&
+        if (avci->skip_samples > 0 && !ret &&
             !(avctx->flags2 & AV_CODEC_FLAG2_SKIP_MANUAL)) {
             if(frame->nb_samples <= avci->skip_samples){
-                got_frame = 0;
                 *discarded_samples += frame->nb_samples;
                 avci->skip_samples -= frame->nb_samples;
                 av_log(avctx, AV_LOG_DEBUG, "skip whole frame, skip left: %d\n",
                        avci->skip_samples);
+                ret = AVERROR(EAGAIN);
             } else {
                 av_samples_copy(frame->extended_data, frame->extended_data, 0, avci->skip_samples,
                                 frame->nb_samples - avci->skip_samples, avctx->ch_layout.nb_channels, frame->format);
@@ -432,11 +370,11 @@ FF_ENABLE_DEPRECATION_WARNINGS
             }
         }
 
-        if (discard_padding > 0 && discard_padding <= frame->nb_samples && got_frame &&
+        if (discard_padding > 0 && discard_padding <= frame->nb_samples && !ret &&
             !(avctx->flags2 & AV_CODEC_FLAG2_SKIP_MANUAL)) {
             if (discard_padding == frame->nb_samples) {
                 *discarded_samples += frame->nb_samples;
-                got_frame = 0;
+                ret = AVERROR(EAGAIN);
             } else {
                 if(avctx->pkt_timebase.num && avctx->sample_rate) {
                     int64_t diff_ts = av_rescale_q(frame->nb_samples - discard_padding,
@@ -452,7 +390,7 @@ FF_ENABLE_DEPRECATION_WARNINGS
             }
         }
 
-        if ((avctx->flags2 & AV_CODEC_FLAG2_SKIP_MANUAL) && got_frame) {
+        if ((avctx->flags2 & AV_CODEC_FLAG2_SKIP_MANUAL) && !ret) {
             AVFrameSideData *fside = av_frame_new_side_data(frame, AV_FRAME_DATA_SKIP_SAMPLES, 10);
             if (fside) {
                 AV_WL32(fside->data, avci->skip_samples);
@@ -464,15 +402,88 @@ FF_ENABLE_DEPRECATION_WARNINGS
         }
     }
 
-    if (!got_frame)
+    return ret;
+}
+
+/*
+ * The core of the receive_frame_wrapper for the decoders implementing
+ * the simple API. Certain decoders might consume partial packets without
+ * returning any output, so this function needs to be called in a loop until it
+ * returns EAGAIN.
+ **/
+static inline int decode_simple_internal(AVCodecContext *avctx, AVFrame *frame, int64_t *discarded_samples)
+{
+    AVCodecInternal   *avci = avctx->internal;
+    AVPacket     *const pkt = avci->in_pkt;
+    const FFCodec *const codec = ffcodec(avctx->codec);
+    int got_frame;
+    int consumed, ret;
+
+    if (!pkt->data && !avci->draining) {
+        av_packet_unref(pkt);
+        ret = ff_decode_get_packet(avctx, pkt);
+        if (ret < 0 && ret != AVERROR_EOF)
+            return ret;
+    }
+
+    // Some codecs (at least wma lossless) will crash when feeding drain packets
+    // after EOF was signaled.
+    if (avci->draining_done)
+        return AVERROR_EOF;
+
+    if (!pkt->data &&
+        !(avctx->codec->capabilities & AV_CODEC_CAP_DELAY ||
+          avctx->active_thread_type & FF_THREAD_FRAME))
+        return AVERROR_EOF;
+
+    got_frame = 0;
+
+    if (HAVE_THREADS && avctx->active_thread_type & FF_THREAD_FRAME) {
+        consumed = ff_thread_decode_frame(avctx, frame, &got_frame, pkt);
+    } else {
+        consumed = codec->cb.decode(avctx, frame, &got_frame, pkt);
+
+        if (!(codec->caps_internal & FF_CODEC_CAP_SETS_PKT_DTS))
+            frame->pkt_dts = pkt->dts;
+        if (avctx->codec->type == AVMEDIA_TYPE_VIDEO) {
+#if FF_API_FRAME_PKT
+FF_DISABLE_DEPRECATION_WARNINGS
+            if(!avctx->has_b_frames)
+                frame->pkt_pos = pkt->pos;
+FF_ENABLE_DEPRECATION_WARNINGS
+#endif
+            //FIXME these should be under if(!avctx->has_b_frames)
+            /* get_buffer is supposed to set frame parameters */
+            if (!(avctx->codec->capabilities & AV_CODEC_CAP_DR1)) {
+                if (!frame->sample_aspect_ratio.num)  frame->sample_aspect_ratio = avctx->sample_aspect_ratio;
+                if (!frame->width)                    frame->width               = avctx->width;
+                if (!frame->height)                   frame->height              = avctx->height;
+                if (frame->format == AV_PIX_FMT_NONE) frame->format              = avctx->pix_fmt;
+            }
+        }
+    }
+    emms_c();
+
+    if (got_frame)
+        ret = discard_samples(avctx, frame, discarded_samples);
+    else
+        ret = AVERROR(EAGAIN);
+
+    if (consumed < 0)
+        ret = consumed;
+    if (consumed >= 0 && avctx->codec->type == AVMEDIA_TYPE_VIDEO)
+        consumed = pkt->size;
+
+    if (!got_frame || ret == AVERROR(EAGAIN))
         av_frame_unref(frame);
 
-    if (ret >= 0 && avctx->codec->type == AVMEDIA_TYPE_VIDEO)
-        ret = pkt->size;
+    if (!ret)
+        av_assert0(frame->buf[0]);
+    if (ret == AVERROR(EAGAIN))
+        ret = 0;
 
-    /* do not stop draining when actual_got_frame != 0 or ret < 0 */
-    /* got_frame == 0 but actual_got_frame != 0 when frame is discarded */
-    if (avci->draining && !actual_got_frame) {
+    /* do not stop draining when got_frame != 0 or ret < 0 */
+    if (avci->draining && !got_frame) {
         if (ret < 0) {
             /* prevent infinite loop if a decoder wrongly always return error on draining */
             /* reasonable nb_errors_max = maximum b frames + thread count */
@@ -490,11 +501,9 @@ FF_ENABLE_DEPRECATION_WARNINGS
         }
     }
 
-    if (ret >= pkt->size || ret < 0) {
+    if (consumed >= pkt->size || ret < 0) {
         av_packet_unref(pkt);
     } else {
-        int consumed = ret;
-
         pkt->data                += consumed;
         pkt->size                -= consumed;
         pkt->pts                  = AV_NOPTS_VALUE;
@@ -509,10 +518,7 @@ FF_ENABLE_DEPRECATION_WARNINGS
         }
     }
 
-    if (got_frame)
-        av_assert0(frame->buf[0]);
-
-    return ret < 0 ? ret : 0;
+    return ret;
 }
 
 #if CONFIG_LCMS2
-- 
2.41.0



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