Add ffmpeg_remuxer

ffmpeg/remuxer.c

@@ -0,0 +1,185 @@
+#include "ffmpeg/remuxer.h"
+#include "opts/log.h"
+
+#ifdef USE_FFMPEG
+static AVRational time_base = {1, 1000LL * 1000LL};
+
+static int ffmpeg_remuxer_init_avcontext(AVFormatContext **context, ffmpeg_remuxer_t *remuxer, int output, int (*packet)(void *opaque, uint8_t *buf, int buf_size))
+{
+  static int avio_ctx_buffer_size = 4096;
+  uint8_t *buffer = NULL;
+  AVIOContext *avio = NULL;
+  int ret = -1;
+  
+  buffer = av_malloc(avio_ctx_buffer_size);
+  if (!buffer)
+    return AVERROR(ENOMEM);
+  avio = avio_alloc_context(buffer, avio_ctx_buffer_size, output, remuxer->opaque, output ? NULL : packet, output ? packet : NULL, NULL);
+  if (!avio)
+    goto error;
+  if (output && (ret = avformat_alloc_output_context2(context, NULL, remuxer->video_format, NULL)) < 0)
+    goto error;
+  if (!output && (*context = avformat_alloc_context()) == NULL)
+    goto error;
+
+  (*context)->flush_packets = true;
+  (*context)->pb = avio;
+
+  return 0;
+
+error:
+  av_freep(&buffer);
+  avio_context_free(&avio);
+  return -1;
+}
+
+static void ffmpeg_remuxer_close_avcontext(AVFormatContext **contextp)
+{
+  if (!*contextp)
+    return;
+
+  AVFormatContext *context = *contextp;
+
+  if (context->pb)
+    av_freep(&context->pb->buffer);
+  avio_context_free(&context->pb);
+  if (context->iformat)
+    avformat_close_input(contextp);
+  else
+    avformat_free_context(context);
+  *contextp = NULL;
+}
+
+static int ffmpeg_remuxer_copy_streams(ffmpeg_remuxer_t *remuxer)
+{
+  for (int i = 0; i < remuxer->input_context->nb_streams; i++) {
+    AVStream *out_stream;
+    AVStream *in_stream = remuxer->input_context->streams[i];
+    AVCodecParameters *in_codecpar = in_stream->codecpar;
+
+    if (in_codecpar->codec_type != AVMEDIA_TYPE_VIDEO) {
+      continue;
+    }
+
+    out_stream = avformat_new_stream(remuxer->output_context, NULL);
+    if (!out_stream) {
+      return AVERROR(ENOMEM);
+    }
+
+    int ret = avcodec_parameters_copy(out_stream->codecpar, in_stream->codecpar);
+    if (ret < 0) {
+      return ret;
+    }
+
+    out_stream->time_base.num = 1;
+    out_stream->time_base.den = 1;
+    out_stream->codecpar->codec_tag = 0;
+    remuxer->video_stream = i;
+    return 0;
+  }
+
+  return -1;
+}
+
+int ffmpeg_remuxer_open(ffmpeg_remuxer_t *remuxer)
+{
+  int ret;
+
+  if (remuxer->packet)
+    return 0;
+
+  AVInputFormat *input_format = av_find_input_format(remuxer->input_format);
+  if (!input_format)
+    return AVERROR(EINVAL);
+
+  remuxer->packet = av_packet_alloc();
+  if (!remuxer->packet)
+    return AVERROR(ENOMEM);
+  if ((ret = ffmpeg_remuxer_init_avcontext(&remuxer->input_context, remuxer, 0, remuxer->read_packet)) < 0)
+    return ret;
+  if ((ret = ffmpeg_remuxer_init_avcontext(&remuxer->output_context, remuxer, 1, remuxer->write_packet)) < 0)
+    return ret;
+  if ((ret = avformat_open_input(&remuxer->input_context, NULL, input_format, &remuxer->input_opts)) < 0)
+    return ret;
+  if ((ret = avformat_find_stream_info(remuxer->input_context, NULL)) < 0)
+    return ret;
+  if ((ret = ffmpeg_remuxer_copy_streams(remuxer)) < 0)
+    return ret;
+  if ((ret = avformat_write_header(remuxer->output_context, &remuxer->output_opts)) < 0)
+    return ret;
+
+  remuxer->start_time = get_monotonic_time_us(NULL, NULL);
+  return 0;
+}
+
+int ffmpeg_remuxer_close(ffmpeg_remuxer_t *remuxer)
+{
+  ffmpeg_remuxer_close_avcontext(&remuxer->input_context);
+  ffmpeg_remuxer_close_avcontext(&remuxer->output_context);
+  av_packet_free(&remuxer->packet);
+  av_dict_free(&remuxer->input_opts);
+  av_dict_free(&remuxer->output_opts);
+}
+
+int ffmpeg_remuxer_feed(ffmpeg_remuxer_t *remuxer)
+{
+  int ret = 0;
+
+  while (ret >= 0) {
+    ret = av_read_frame(remuxer->input_context, remuxer->packet);
+    if (ret == AVERROR_EOF) {
+      ret = 0;
+      E_LOG_DEBUG(remuxer, "av_read_frame: EOF", ret);
+      break;
+    } else if (ret < 0) {
+      E_LOG_DEBUG(remuxer, "av_read_frame: %08x, pts: %d", ret, remuxer->packet->pts);
+      break;
+    }
+
+    if (remuxer->packet->stream_index != remuxer->video_stream) {
+      av_packet_unref(remuxer->packet);
+      continue;
+    }
+
+    AVStream *in_stream = remuxer->input_context->streams[remuxer->packet->stream_index];
+    remuxer->packet->stream_index = 0;
+    AVStream *out_stream = remuxer->output_context->streams[remuxer->packet->stream_index];
+
+    int since_start = get_monotonic_time_us(NULL, NULL) - remuxer->start_time;
+
+    // TODO: fix a PTS to be valid
+    remuxer->packet->pos = -1;
+    int pts = remuxer->packet->dts = remuxer->packet->pts = av_rescale_q(
+      get_monotonic_time_us(NULL, NULL) - remuxer->start_time,
+      time_base,
+      out_stream->time_base
+    );
+ 
+    ret = av_interleaved_write_frame(remuxer->output_context, remuxer->packet);
+    av_packet_unref(remuxer->packet);
+
+    if (ret == AVERROR_EOF) {
+      E_LOG_DEBUG(remuxer, "av_interleaved_write_frame: EOF, pts: %d, since_start: %d", ret, pts, since_start);
+    } else {
+      E_LOG_DEBUG(remuxer, "av_interleaved_write_frame: %08x, pts: %d, since_start: %d", ret, pts, since_start);
+    }
+  }
+
+  return ret;
+}
+#else
+int ffmpeg_remuxer_open(ffmpeg_remuxer_t *remuxer)
+{
+  return -1;
+}
+
+int ffmpeg_remuxer_feed(ffmpeg_remuxer_t *remuxer)
+{
+  return -1;
+}
+
+int ffmpeg_remuxer_close(ffmpeg_remuxer_t *remuxer)
+{
+  return -1;
+}
+#endif